Corsi Block-Tapping Test

The  Corsi Block-Tapping test, sometimes referred to as "Corsi Blocks", is a classic test used as a visuo-spatial version of digit span.  Instead of hearing digits, you see blocks attached to a board, and the experimenter points at a sequence of blocks which must be reproduced by the subject.  Blocks are used because it allows them to be numbered on their back, hidden from the subject but visible to the experimenter who sits across the table.

Here is a 3D rendering of the block test that Derek from University of Iowa put on the internet: