Algodoo

You can do this with a single laser:

Delete one of the lasers.

Define: _mult := 0

postStep = (e)=>{
keys.isDown("up") ? {
_mult = 1.01;
maxRays = 1
} : {
keys.isDown("down") ? {
_mult = 0.99;
maxRays = 1
} : {
maxRays = 0
}
}
}


Partial "onLaserHit" script: surf := (readable(e.geom)).surfaces * _mult;

Delete laser "Activation Button"

Th... Th... Th... That's all folks!

Good idea. Done.

Very nice and simple!

Not like that,Xray,just like that, and few instructions:

There are two frogs,and so a frog has a sign like this:"^"and a down arrow.
So delete the lasers(actually Xray is most correct.).

Done.