“Concentrate! Concentrate now!” shouts Mahmud in a high-pitched voice, prompting giggles from the 40 rapt kids staring up at him.
He and his friend Muhammad Ayub, decked out in bright orange vests, are volunteers who travelled hundreds of kilometers to the quake and tsunami-ravaged Indonesian seaside city of Palu from the island of Lombok -- which this summer was itself pummeled by a series of deadly quakes.
The pair are not medics or engineers but storytellers, trying to brighten up the lives of children thrown into a world that even adults struggle to comprehend.
Over 1,500 people have so far been confirmed dead since last week's double disaster, with tens of thousands forced out of their homes and into evacuation centers.
“We want to build up their spirits after the tsunami, there is a lot of trauma,” said 30-year-old Ayub, as Mahmud led the makeshift outdoor classroom in something like an Indonesian version of “heads, shoulders, knees and toes”, to uproarious laughter.
“It's great, we are having fun here,” said 13-year-old Fatir, who exclaims “no way!” when asked if living a tented camp in a car park -- with only a tarp and trees for shade -- is difficult.
It is for all intents and purposes a camp for the displaced, but as they run about, play badminton or kick a football around, the kids can forget about what has happened to them, if only for a moment.
Nearby four-year old Difrani picks up her brother Nabil, who is still in pajamas, and jiggles him around.
Her mother says she has no toys to give them, but wrestling around with the one-year-old -- who has a bit of a cold -- is Difrani's fun, even if Nabil looks none too pleased.
The whole family ran to the hills when the earthquake and tsunami struck and this is their life for the foreseeable future.
“She won't be going to school for a while, all the schools are damaged,” said their mother Dian.
“But they are happy playing around with their cousins and new friends.”
There are cheers and hands shoot into the air as Mahmud, who only gave his first name, starts another story under the trees nearby.
Some in Palu desperately need medicine, some need a shelter over their heads -- but others just need a good giggle.
Save the Children say that some 600,000 children have been affected by the quake, with many separated from their families and sleeping among ruins in Palu.
Lombok, a popular holiday island next to Bali, has been battered by a series of quakes since July, which have killed more than 500 people and forced hundreds of thousands into evacuation shelters or tents.