Standing in two rows with knees bent, 10 men slowly pushed their palms out against a slight breeze during a Chinese "tai chi" martial arts session on the ground floor of a public housing block.
In similar places across the island, Malay weddings were taking place and Indian children shared playgrounds with kids from other races, including the occasional white boy or girl from expatriate families renting public flats.
Just a typical weekend in Singapore's "void decks" -- the shared open spaces under high-rise government-built apartments scattered across the densely populated city-state.
With more than 80 percent of its ethnically diverse people staying in public flats -- and foreigners now accounting for a third of the population of five million -- void decks are an important part of daily life in Singapore.
Like blank canvasses on which Singapore's ethnic rainbow is painted, void decks host everything from weddings and funerals to romantic trysts and day-long chequers sessions that draw retirees from all ethnic groups.
"The void deck is a place for 'collective idling'," said Chua Beng Huat, a professor with the National University of Singapore's sociology department.
More than that, sharing the space is also part of Singapore's strictly enforced social policies aimed at ensuring harmony among the races in a region often torn by religious and ethnic strife.
Flats in every public housing estate are apportioned in accordance with Singapore's ethnic mix -- 77 percent Chinese, 14 percent Malay and eight percent Indian, based on a 2000 census -- to prevent racial enclaves from forming.
Ethnic harmony is paramount to Singapore, which experienced race riots in the 1960s and is keen to avoid the tensions that periodically flare up in neighbouring Malaysia.
In two recent cases played up by local media, a Christian pastor was forced to apologise publicly for slurs against Taoists and Buddhists, while three Chinese youngsters are being investigated for anti-Indian rants on the web.
Prime Minister Lee Hsien Loong has used the void decks to underscore the need for ethnic tolerance, citing a rare incident that could have caused racial tensions to flare.
Lee related in a national day speech last August that families organising a Chinese funeral and a Malay wedding were in a tussle for the same void deck, but the situation was defused with the intervention of community leaders.
"If such an incident had been wrongly handled and you have a case which escalates into a racial or a religious conflict, then one case is bad enough," he said.
For most Singaporeans, void decks are simply a neutral place to hang out and mix it up.
Wong Phui San, a 59-year-old retiree, takes a short bus ride to another district to play chequers because players there are up to his skill level.
"What else is there to do if I don't come here? This way I don't have to spend money. I'll only need to take the bus and I can spend my day here," said Wong.
Weddings of ethnic Malays are often held at void decks on weekends.
Planners are called in to transform the space into a ballroom as the cement floors are carpeted, walls draped with long cloth and flowers, and a temporary dais is set up for the bride and groom.
"One main reason why the void deck is a popular wedding venue for the Malays is that it's cost-efficient," said Nurdyana Lim, a Malay wedding planner.
The large scale of Malay weddings evolved from the village tradition of involving the entire family, long-lost relatives and neighbours to help out with the ceremony in the spirit of community, she said.
"They can invite more than 1,000 guests and not worry about having to spend as much as if they were to book a hotel ballroom," she added.
Fitness buffs use void decks instead of paying gym fees.
"We like having the open space because even if we get more members, we will still have enough room to accommodate them," said Bill Chan, a 34-year-old engineer who regularly attends tai chi sessions in one block.
Most void decks are equipped with stone tables, benches or bicycle racks and are situated near lifts and playgrounds.
Some are used to house childcare centres, convenience shops and senior citizens' corners equipped with a TV set, toilet, pantry and stone tables imprinted with chequerboards.
During funerals held by the ethnic Chinese community in the areas, a tented section hides the altar and the open coffin from view while sympathy wreaths are lined near the entrance.
Tables and chairs are provided for mourners who come to the wake, which spans three to five days.
On the last day of the wake, a funeral band trails the procession from the void deck to the crematorium or cemetery -- with neighbours from across the ethnic spectrum often taking part.