Would you send a text message every day to someone for a year, knowing you would never get a reply? Would you shun traditional art materials such as paint, easel, canvas and brushes to create a full-colour piece of artwork daily using just your index finger on the screen of your iPhone?

A Singapore resident does. Unfailingly. Then he texts it to someone who evaluates it from about 6,000km away.

It's not the most traditional interaction between untrained artist and untrained critic, but it's an unfailing daily ritual between two people who cherish their long-distance connection.

The critic cannot write. Nor can he text. But he eagerly awaits the daily artwork.

The artist? Oh, he's just a rank amateur. An untrained, recreational artist. In primary school, he drew only planes and soldiers. Not very well, he says. Just black-and-white sketches, using his school pencils that had little erasers attached to their tops, so he could rub out lines that were awry. And there were many lines, he says, that were awry.

Then he went joyfully to a boarding school and awoke each morning to see the dawn light turning the deep snow momentarily pink on the third-highest mountain in the world. He loved the fact that his art classroom had broad glass windows that opened out onto the mighty peaks that attracted the best and bravest mountaineers from around the world.

Gradually, what he drew began to change. The mountains, in their many moods, began to appear in his sketches. Sometimes he compromised and drew squadrons of jets flying over the peaks.

Then, he had to choose his subjects for senior school and he opted for maths, physics and chemistry. There would be no more art in his life. Or so he thought.

He was 40 when, on a whim, he bought a watercolour sketch pad, with the fibrous paper that was specially designed to soak up paint. He used his children's paints and brushes to create images of the city around him. Sometimes, he would frame a painting and give it to one of his many friends around the world.

Imperfect art, he would say, but straight from the heart. That was all that mattered.

Then, last Christmas, just after he turned 60, he was in a shopping mall with his only grandchild, who had just turned three. The little boy began reading aloud the letters in a sign outside a shop and the man began to think. He wondered how he could empower the child's interest in letters and words.

So, after the holiday ended and the man and his grandson were separated once more by several time zones, the amateur artist had a light-bulb moment.

He told the little boy's mother that he would text a simple, daily drawing with a one-word caption in capital letters to encourage the child's interest and ability.

His early drawings were basic stick-figure sketches that took no more than a couple of minutes. Then the man became more adventurous and the daily drawings became more ambitious, more complex, more testing - but infinitely more rewarding.

The little boy noticed the improvement too, remarking recently that his grandfather's ability had improved considerably. So the self-taught artist continued.

Now, he sets aside at least an hour each day doing the finger sketches on the screen of his iPhone, experimenting with combining a limited range of colours to create rust (grey, pink and orange) in his artwork of a tractor from the animated film Cars, and to mimic the gold (grey and yellow) on the metal skin of C-3PO from Star Wars.

Then he waits to find out whether his artwork meets with the little boy's approval. Every artist needs a critic, after all.

Not every one of his experiments works. One day, the man drew a cartoon representation of a flamingo, exaggerating the bird's famously flexible neck. The boy said his grandfather had to try harder because the bird did not look real. The next day's drawing, carefully realistic this time, got the thumbs up.

But the real reward is that child and grandfather have both learnt. In truth, the man says - to his abiding surprise - he has probably learnt much more through the process than his grandson.

So, if you ever want to find out how to do a full-colour, finger drawing on your smartphone, come and ask me. I'll show you, in detail, how I do the daily drawings for my precious grandson.