Error while running event aurelia::on_tick (ID 0)
aurelia/scripts/screenshake.lua:41: attempt to get length of local 'rocks' (a nil value)
stack traceback:
aurelia/scripts/screenshake.lua:41: in function 'spawn_rocks'
aurelia/scripts/screenshake.lua:6: in function 'shake'
aurelia/control.lua:35: in function <aurelia/control.lua:26>
