Auto Spleef! is a map that auto regenerates spleef so you don’t have to reset the map and can keep replaying.
Since it’s hard to explain I’ll copy paste what the creator said;
How does it work?
The contraption is quite obvious once you play, but here it goes! Underneath the floor of quartz there are cobble generators, under the cobble generators, there are pistons which push the cobble out of the generators in front of other pistons.
The pistons in which now have cobble in front of them push the cobble out into the arena to create the arena floor. All of this is hooked up to a hopper timer.
A hopper timer is a timer that measures the time it takes to fill all of hopper b with the items in hopper a, once this has happened, they switch directions and it measures from hopper b to hopper a.
They hopper design I used originated from Mumbo Jumbos youtube channel but I had to change like 2 pieces of redstone to make it work in MCPE.