The grenade tool

In this problem, add a 'grenade' cursor tool which will remove all nearby critters when you click it. When you left-click with the grenade tool, you destroy all the critters whose center is within some fixed Real _grenadedistance of the cVector point corresponding to the cursor click. Or maybe it will be better to just destroy the first int _grenadekillpower count critters that you find within _grenadedistance, counting down from the closest ones. This way, if you have a really deep stack of critters, like the Game | Huge selection, you can have fun using repeated grenade hits to blast your way down. Try and think of a game where the grenade tool would serve a useful purpose.

It would be nice in the Dambuilder game to have a rotating tool, that is, a cursor tool so that if you left-click with it, it will rotate a selected wall critter a bit counterclockwise. See if you can design and implement this.