i used stain for the wood
first I stained one side
and as soon as this was dry the other
this can cause the wood to warp
there are several solutions for this
you can press them down with magnets when lasering
you can hold the wood over boiling water for a few seconds
then the wood will be straight again (then put some weight on it to keep it that way)
red is cut
blue is engrave
you can vary the size
you should always make sure that everything is well balanced on the wood