@RichardCuthbert You fill the entire floor with Zappers, then you place a yellow bot. Play the level, and the game will crash. Open the level again and you'll be able to place multiple B-bots. Then remove the Zappers and voila! Note that the B-bots will be invisible at first, but will appear when you play the level. I forgot who discovered this glitch initially, but it was made known by @Caken and months later @meko used it and explained it in a detailed way, as Caken's instruction were a little vague.
Messy and chaotic. Seems that you just put a random amount of B-bots at random places, with some on top of each other and some even headless. It just looks like a random, chaotic test level to see how the bug works. If it is, then please say so...
