Bongo is a program that asks the user to solve a visual pattern recognition problem. In particular, Bongo displays two series of blocks, the left and the right series. The blocks in the left series differ from those in the right, and the user must find the characteristic that sets the two series apart. A possible left and right series are shown below:

(These two series are different because everything in the left is drawn with thick lines, while everything in the right is drawn with thin lines.)

After seeing the two series of blocks, the user is presented with four single blocks and is asked to determine whether each block belongs to the right series or to the left. The user passes the test if he or she correctly detemrines the side to which all the four blocks belong.