Prime Minister Lee Hsien Loong had a habit of tugging his shirt sleeves near his shoulders whenever he was engrossed in a conversation. So did Mr Lee Kuan Yew.
This was one of the matter-of-fact observations the elder Mr Lee made when he was asked if father and son had similar traits. Tugging his own sleeve, he said: "I did not know how much like me he was until I watched him on television one day."
In another interview, he cited the work of British psychologist Hans Eysenck, who said boys tend to follow their mothers, and daughters, their fathers.
"Loong is a different personality from me. He's more, how would I say, equable - less intense than my daughter who takes after me," he said.
As someone who believed deeply in the heritability of genes, it was a subject that intrigued him. However, others were probably more seized by the possibility that the father may have succeeded in transferring all of his political DNA to the son.
Do they share the same political values and instincts? Such questions have been aired in kopitiam circles as well as the conversations of the creme de la creme. At the heart of the fixation for some is the fear that the younger Lee would lack his father's political strength and skill to do whatever had to be done. Others have the opposite fear, that should the time come for change, PM Lee would be unable to break free of his father's legacy.
It is difficult to compare the two, given that they belong to very different periods. Although their years in Cabinet had an extraordinarily long overlap of 27 years, their premierships were separated by 14 years of the Goh Chok Tong administration.
The elder Mr Lee's Singapore was associated with the drama of nation-building and high growth from a lower base. PM Lee's is a more stable Singapore, but one that faces the challenges of a maturing economy and a more demanding electorate.
Despite the differences, such is the senior Mr Lee's hold on people's political imagination that the question continues to arise: How much has he passed on to his son?
While much has been written about PM Lee's growing-up years, from their family holidays at Changi or Cameron Highlands or in Cambodia, to constituency visits, he has rarely spoken about the influence his father had in shaping his political beliefs, even though he is leading a movement founded by his father and his contemporaries.
During an interview in June 2013 - as concern grew about his father's frail health nearing his 90th birthday that September - PM Lee reflected on the impact his father had on his life, the personal and the political.
Recalling his childhood, he remembered a father who, though not always physically present in the house, was well apprised of what was going on in their lives.
"He was a very strict, good father. He left a lot of the looking after of the family to my mother because he was always busy with politics and with his responsibilities," said PM Lee. "But you knew he was there, you knew what he thought, you knew what he expected. Very strict. And if he disapproved of something, he didn't have to say a lot, you knew it."
The eldest of three children, PM Lee was born in 1952, two years before the PAP was founded. His fondest childhood memories include the short holidays and relaxing activities they had as a family. He recalled that when he was five or six, he would go in the evenings to Tanglin Halt to look at the trains go by.
Holidays to Cameron Highlands were "a great thrill and outing for us". He remembered the quaintness of breaking the journey in Kuala Lumpur and staying at the railway station's hotel, which gave him a chance to look at the trains on the platform.
He also learnt to play golf with his father: "So, for quite a number of years, I would play with him, and he would take me around the course when we were on holiday or here at Sri Temasek and on the Istana course. And that was a chance to spend time with him and chat with him."
As with traditional Asian families, hierarchy was respected and formalities observed. "He's not very demonstrative. And our family generally is not very touchy-feely. But it's a very deep respect and regard. He took us seriously and we held him in high respect. I think if you compare it with parents today and their children, they would describe it as a much more formal relationship.
"Today, I think people are much looser in the way you treat your parents, what they say, what they think, how you would argue with them. With us, well, we were a different generation."
As children of the Prime Minister, they were expected to behave properly and not throw their weight around. They were not under pressure to excel in school, although all three did."I was not the top student in the class or in the school. But as long as you're doing your best and you're managing, well, they were okay," he said.
If the children had an interest in something, the parents would help them pursue it. He himself, for example, decided to learn music after picking up a recorder bought for one of his siblings. From learning to read music, he decided to play the clarinet in the band and, later, the tuba. But there was no pressure to go through the hoops of examinations to polish his skills.
"In that way, it was a relaxed family. But they expected us to behave well and speak properly, not sloppily, use correct language and no bad language. I think those are things that they are stricter about than many parents today," he said.
Both parents stuck to a policy of not interfering with their children's own families.
However, the father did pen words of advice to his two sons when they got married.
"It's advice on how to have a happy marriage, speaking from his own personal experience. He took a lot of trouble keeping in touch with us. When we were away, he would write to us. And my mother would write to us every week. And I would write back," recalled PM Lee.
His mother's letters were handwritten whereas his father's were typewritten. "His letter would be dictated, typed, and then it's typed double or triple space, and then he would go through and correct the typed version, and then add stuff and maybe have another paragraph or two at the end in writing, and then he would send it to me in that form. To think of the effort… substantial pieces, maybe five, six pages, maybe more. I still have them all stored away somewhere," said PM Lee.
"I replied, also quite long letters, every week."
Personal tragedy struck PM Lee twice. In 1982, his first wife, Dr Wong Ming Yang, died from a heart attack. In 1992, when he was deputy prime minister, he fell ill with lymphoma. Recalling those life-changing events, he said of his father: "You depend on him for support."
Asked about his bond with his father, he said: "When you needed him, he was there. In a crisis, he was the key person in the family."
As for his decision to enter politics, PM Lee was unabashed: "He's had a very big influence on me. It's hard to say but he probably made me who I am, not like him but I learnt a lot from him."
It was Mr Goh who urged him to consider joining politics, PM Lee said, but he does not deny that his parentage had an influence on his willingness to serve.
"If he hadn't been my father, I don't know," he said. "I might still have found my way into politics. Many of the other ministers and MPs have found their way into politics without having had the PM for their father. Maybe if he hadn't been my father, I might have felt less of a sense of responsibility that I had to take this up and do it."
Having seen his father put his life and soul into Singapore, he felt compelled to do the same.
"If it hadn't been him and I had been carrying on with my life and you asked me to... well, I would say, let's give it a try. It's a challenge.
"But you won't have that same deep feeling of what is involved and how much it can mean to you. But having seen him struggle with his languages, having seen him go on the constituency visits, having seen him recording Battle For Merger, slogging away, and the speeches and the rallies, and the persuasion and campaigning, you know what you are in for.
"And you know what it's about, which is an advantage but of course it also puts a greater burden on you in terms of what you expect of yourself and what others expect of you."
Asked what his father thought of him, PM Lee was clear that he would not be burdened by that. "Not for me to judge," he said simply. "I'm sure he believes that I can do better."
PM Lee admitted readily that he is "temperamentally not like him". "He's a lot harder, more willing to come upfront in a very direct way. I have my preferences how I would like things to be done, but I don't spoil for a fight. He often does."
He said it was the duty of those who came after Mr Lee to safeguard and build on what he achieved and to take it to another level with a new generation of Singaporeans.
A key task for the current generation, he said, is to persuade people of what's at stake. Indeed, that was Mr Lee's key strength: persuading people.
Reflecting on the lessons his father taught him about politics, PM Lee put it this way: "You must know what you want to do; it's not just following what people want or what the crowd says. I think that's the first one. You must have some idea what you want to achieve.
"Secondly, you've got to persuade people and bring them along, so you are not living on your own. Follow me, I'm leading in front, but my people are with me.
"Thirdly, it's not just a matter of logic and argument but also of emotional persuasion and also of people sense, to be able to read people, to manoeuvre, to get through what you need to get through, so that things will be done. And there are a lot of very clever people in the world but not all clever people make good political leaders. In my father, we had, I think, a very exceptional combination."
His father had an "instinctive ability" to read the political situation and to navigate a route to get the best for Singapore. "Whether you're discussing National Service policy or whether you're discussing getting the best terms for water or for railway land, well, to know how to put the argument across and make the deal which is in line with your overriding interest," he said.
"I think he had that instinctively, partly the way he was born, partly the life he lived through, having to survive the Japanese Occupation, having to negotiate with the British, having to fight the communists. If he didn't have those or didn't develop those, he would not have survived them."
Asked what he admired most about his father, Mr Lee said it was that he had given so much to the country. "And to be so singularly focused on this obsession to build up Singapore, to make it safe, to make it better and to create something for Singaporeans which actually we're not entitled to expect, but which we have done, not him alone but with his colleagues and with the population. I think that's quite exceptional."
Mr Lee steered the country from its independence struggle through the difficult merger years and then to ensuring nation-building, managing prosperity and ensuring succession.
At the core of it all, he remained aware of change and adapted readily to it. "I think that's very unusual," said PM Lee. "I watched him in Cabinet. As the oldest member, sometimes he's the most radical."
He cited the example of casinos, which Mr Lee opposed for decades but eventually, when he came around to the Ministry of Trade and Industry's argument for them, pushed for them, arguing that the world had changed and Singapore must change along with it. "This ability to keep current and to keep young intellectually, mentally, I think that's very remarkable. But it's not easy."
Whether it was altering the education system or introducing new housing schemes or about changing social mores, often Mr Lee "knew why and he pushed us to go further, because the times have changed".
The PM related an anecdote about some Western tourists who sunbathed topless in Sentosa and were to be charged in court. He received a note from his father, querying if the Government needed to be "so puritanical" and asking to "just let it be". PM Lee rejected the suggestion, saying our society was not quite there yet.
"We have to enforce our rules but of course as times change, I think the expectations will shift. So his attitude was practical, was current and he moved with the times - often ahead of the times. I think in many areas he has views which many Singaporeans would think very radical."
Asked how they dealt with each other and what advice his father gave him when he became Prime Minister, PM Lee said: "I can't remember anything specific which he said but I think it gave him a lot of satisfaction that the system of transition, of renewal, was working, that not only had he managed to hand over to a successor but his successor had done, had worked up in a job, succeeded. And another transition had taken place to a third generation.
"Not just me but also my peers - George (Yeo), Wong Kan Seng, Teo Chee Hean, Lim Hng Kiang and company. I think that was one of the most amazing things, that he could stay in Cabinet with his successors, and it was a valuable experience for the successors as well as for him.
"And I've talked to some other prime ministers who have had former prime ministers to live with and they tell me they cannot imagine how it can be that your predecessors are in Cabinet and you're still managing. I said, well, we're different from you. And my predecessors are different from your predecessors."
It was possible because Mr Lee knew how to "guide without asserting his will in a hard way and he knew when to let things go and to take a new direction". He went along with the younger leaders' ideas and often pushed them to go further. But he had definite ideas on some issues, such as the greening of Singapore.
PM Lee recalled how, several years ago, the Istana staff wanted to remove a few trees to improve visibility for security. "I was going to agree. And he sent me a note to say, are you sure you need to do this? Why don't you leave it be? This place is green and we've made a point of making this place green. And you've got birds, you've got the wildlife, and you want to keep it like that. So in the end, I didn't cut the trees down."
Having watched his father at work over the years, what stood out was Mr Lee's approach of unrelenting effort and the belief that things could be better. "Just watching him and the way he fought and he worked and he struggled with all the issues and challenges, I think that's a great inspiration," he said.
"Policies, you can understand, you can work out intellectually what is it that needs to be done. But to see him sweating away with his languages, particularly Mandarin, every day listening to the tape, having a teacher, then exercising; exercising while listening to the tape playing; getting the phrases, keeping the phrases, refreshing the phrases, studying, bringing the tutor home on weekends in the study; learning Mandarin, learning Hokkien, especially during the '60s. It's a tremendous slog for him.
"And even until old age, he's still taking lessons daily, still keeping the language alive because he's made such a big effort, he doesn't want to lose that. I think that's an amazing personal example."
In the course of many interviews throughout his life, the elder Mr Lee was most often reluctant to wrestle with the what-ifs and what-could-have-beens. True to his personality, he allowed no room for regret.
"That's for wimps" is the implied sentiment. He would often throw his head back to let out a laugh or wave a hand as if to literally deflect the question, and say: "That's a parlour game."
But this is his son and so one tries to ask: What is the most misunderstood thing about Mr Lee Kuan Yew?
"I think he doesn't mind what no one knows about him. People think of him as an austere, logical and cerebral sort of person. I think he has strong feelings about quite a number of things, and also in his personal relationships - with my mother, with the kids. He may not show it but feels it."
Asked what he would miss about his father when the time came, he said: "So many things. I think the key thing is that with him, you will not lose, you will be all right and you will come through. And that sense of confidence and that trust in a person because of the experience, what he has gone through, because of what he has done, because of what he has contributed and demonstrated, is not something which you can replicate with any other person.
"He was unique, he played a unique role in Singapore, and I think we've been very lucky to have him."
Asked how he thought his father would like to be remembered, his face scrunched up, his eyes flashing impatience.
Then he replied: "He never troubled himself with that question either. I don't know... He's a father, he's a father of the nation. He made this place."