Error while running event glowing_trees::on_nth_tick(10)
__glowing_trees__/control.lua:830 bad argument #2 of 5 to 'format' (number expected, got string)
stack traceback:
(C):in function 'format'
__glowing_trees__/control.lua:830: in function 'unique_groups'
__glowing_trees__/control.lua:882: in function
<__glowing_trees__/control.lua:843>

Oops, thank you for the report! That was a slight oversight on my part and should now be fixed in version 0.0.4 :)

Thanks for the quick fix, it is working for me.