Earlier this month, while working at home, I wanted to rest my eyes so I looked out my window - and saw a crumpled tissue paper quietly floating down and landing on the ledge outside. I realised there were a couple of dried-up, blackened bits of tissue beside it, which seemed to have been there for some time.

It's the kind of thing that's easy to overlook when one spends most of the time outside the house. But being holed up at home amid the Covid-19 pandemic has forced us to notice how our neighbours' habits could affect us and our environment.

There was another discarded tissue and a newspaper page outside my window three weeks later, so I posted a note on the condo app, asking neighbours to throw their trash properly.

On Friday, ST senior correspondent Joyce Lim's article - No one in my family can get a good sleep: More complaints about noise and cigarette smoke during circuit breaker - touched a nerve among many readers, some of whom shared their experiences on ST's Facebook page.

One Facebook user, ML Tham, wrote: "I'm surrounded by smokers. At times, smell comes (into) my living room window, kitchen window, corridor. Opening and closing windows has been a habit."

Others talked about the dangers of second-hand smoke and how some residents treat common areas as "secret corners for smoking".

Facebook user Tay Yu Wee Devan complained about high-rise littering, especially lit cigarette butts at service yards, balconies and common areas.

Another wrote about the noise coming from upstairs from her neighbour, who has kids running across rooms, dragging furniture and dropping things on the floor after 11pm and until past midnight. "If they did all these in the day time, I have nothing to say. But come on, other people need to wind down and sleep... Really very inconsiderate," said Facebook user Wang Jiayi.

Some readers have written to ST about loud noise and smoke from their neighbours' units.

In Ms Lim's article, she reported that the National Environment Agency (NEA) has been getting more complaints about smokers since circuit breaker measures kicked in on April 7.

It received 11,400 cases of feedback related to smoking in the first four months of the year, which is about 2,000 more than in the same period last year. The increase was largely related to smoking in corridors, staircases and residential homes.

NEA said it has been working with the relevant authorities and town councils "to encourage smokers to be considerate to their neighbours and smoke away from the windows".

Some readers, however, feel that more should be done.

"What do you mean by closing our windows to prevent smoke from coming in... I tried for two consecutive weeks and the smoke still comes in and worse it stinks (up) my whole bathroom!!" commented Mich Tan.

Another Facebook user Boey Kam Weng suggested requiring smokers to close their home windows when they smoke, just as those inside their cars may light up as long as their windows are fully wound up and no second-hand smoke is expelled into smoking-prohibited places.

But a parent with a young child said that while he doesn't like the cigarette smoke coming into his house, he is willing to let it pass.

"I know everyone is cooped up at home. People are stressed. People do what they can to keep themselves sane. If I confront, tensions might increase and it will not help anyone. As long as it's not an extreme nuisance, I think we can live and let live. I will find a way to manage," said Kel Lee.

These are issues that are unlikely to go away soon, with no easy solutions. Being more mindful about our actions and avoiding causing harm to others is the least we can do.

NINJA SQUIRREL

A man in the United States wanted to stop squirrels from stealing bird food in his yard. After failing to find a squirrel-proof feeder, he built an elaborate eight-part obstacle course inspired by reality show American Ninja Warrior.

"I've basically been spending the whole quarantine engineering my revenge," inventor Mark Rober tweeted. The engineer, who previously worked at Nasa and Apple and has many viral videos to his name, posted the video of the course on YouTube on May 25.

"This course is extremely challenging," he said, and "is not for the timid of heart".

There's a Bridge of Instability and Pitchfork Tumblers of Treachery, among others.

Mr Rober explained the mechanism behind the contraptions and threw in some physics lessons too.

It seemed daunting, but after several hilarious attempts over a week, four squirrels eventually found their way to a walnut feast.

"I will admit, in hindsight, that I completely underestimated my adversary," Mr Rober said.

The full video has been viewed 18.8 million times on YouTube and shared more than a million times on Facebook.

"I would watch a whole season of Squirrel Wipeout," said a viewer.

Former MythBusters co-host Adam Savage praised Mr Rober, tweeting: "The limits of staying within his own property for two months are no limit at all, it turns out. Brilliant."

We've all been challenged to think of creative ways to solve problems during this period and it's quite inspiring to see what some people can come up with when they put their minds to it.