English: A decision tree for four shapes. Based on a figure from (2001). "The physics of forgetting: Landauer’s erasure principle and information theory". Contemporary Physics 42 (1): 26., the caption of which says:

An example of a decision tree. Two binary choices have to be made to identify the shape (triangle or square) and the orientation (horizontal or rotated). In sending with equal probability one of the four objects, one therefore transmits 2 bits of information.