It is a simple apple-shaped toy that lights up and plays a tune when a button is pressed. After a few seconds, a worm pops out of the top of the apple.
Each time Muhd Fahmi, 14, plays with this favourite toy of his, he smiles and his eyes light up.
Toys such as this have expanded the world of Muhd Fahmi, who was born with severe intellectual and physical disabilities, by firing up his imagination.
But a lack of muscle control means he needs his mother to press the toy's button for him each time he wants to play. So, whenever she is unable to do that for him, he ends up throwing a tantrum by banging his head on the floor.
A group of engineers and other professionals picked up on this problem and decided to put their skills to good use.
They dismantled the battery-controlled toy and rewired it so that it could be controlled by a bigger button or external switch.
Last year, the group - called Engineering Good - along with trained volunteers and some parents and staff from special needs schools, came together to modify the toy.
About 40 modified toys were then donated to the AWWA School for students with special needs.
"My boy now enjoys playing with the toy himself and he can focus better so sometimes these toys are used as part of his therapy sessions," said Muhd Fahmi's mother, Madam Faridah, 50.
Besides "hacking" toys, Engineering Good also designed science experiment sets for the Cerebral Palsy Alliance Singapore (CPAS) so that its students could do more hands-on learning on abstract concepts such as light and electricity.
For instance, students elsewhere usually set up electricity circuits using crocodile clips; but manipulating the clips requires fine motor skills that the students do not have .
The group came up with a prototype set that uses magnets with copper tips instead that could slide easily into place for circuits.
"Usually, our older kids learn about this topic by watching videos or looking at pictures but, with these sets, even the younger kids can try it for themselves," said Ms Jasmine Hon, 32, a CPAS teacher.
"Special needs children learn better with their senses so they tend to remember concepts better when using the sets," she said.
The group has designed eight different types of science sets so far and will be sending 20 sets to CPAS by the end of the year.
Other ongoing projects include working with AWWA to motorise the school's flag-raising and lowering process every day with the push of a button. Participating in the flag-raising ceremony gives the children a sense of pride and patriotism but only a few of them have the physical ability to do so.
The group is also working with youth volunteers to come up with a device to help children who cannot speak. By pushing a button, sentiments such as "I want to go to the toilet" and "I am hungry" can be made known more easily to teachers or parents.
"We saw a clear gap to fill in coming up with low-cost solutions to enhance the learning and quality of life of children with disabilities," said Ms Hannah Leong, 29, executive director of Engineering Good.
She said: "The special needs schools told us commercial vendors don't want to do it as it doesn't make business sense while the projects that tertiary institutions come up with prioritises academic research rather than such practical needs."
She is the only full-time worker with the registered charity. Helping to run the charity are seven volunteers who are engineers or come from fields such as accounting, banking and marketing.
Other volunteers, who come from the public and its student chapter at the National University of Singapore, make up the numbers for its projects and workshops.
The charity is funded by corporate sponsors, government grants and public donations.
"When people think of engineers, they think of numbers and spreadsheets but, actually, their skills can impact lives," said Ms Leong, who quit her job with a social enterprise in Laos to return to Singapore to start Engineering Good.
She said: "We want to engineer a better world."