This is a light sensitive robot. It follows light. It can even do a wheelie. It detects the light by its eyes(LDRs). Pretty simple circuit consisting of four transistors. The circuit can be divided into 2 independent symmetrical parts. The right motor rotates when the left LDR detects light. The left motor rotates when the right LDR detects light. When both LDRs detect light, Both motor rotates and the bot goes forward. I got the basic circuit diagram from the e-book '1-100 Transistor Circuits'.