You might want to add to that first puzzle that the points ABC and XYZ are considered lines themselves. By making them mere markers (by that i mean, that you could pass through one point on the way to another, so long as you don't touch another connecting line) it actually is possible. but yeah, otherwise, you can only knock all but one line out. Not trying to nitpick, there are just tons of problems out there that require a backhanded solution like that.
http://img.photobucket.com/albums/v3...lesolution.jpg
anywho, run this one. should be fairly simple and make room for a harder puzzle. Using a three gallon and a seven gallon container, and making no marks on the container (no saying "mark three gallons on the seven..." etc.) measure 5 gallons.
Alos, simple enough, arrange 12 lines of equal size and length, create 6 polygons of equal size and shape.