[thallukrish]

I can relate to the author's curiosity of how such a random movement ends up doing a near perfect clean in the given time. I have tried to understand how my basic Roomba works as well. One simple algorithm could be that it is simply storing the path it travels randomly like a criss-cross, zig-zag path and ends up filling a imaginary polygon with those zig-zag movement. That's probably the reason it does not get stuck doing the same part of a room again and again.