This paper describes the properties of a set of puzzles that are behaviorally similar to those of the common Raven Progressive Matrix test. Our puzzles consist of a three-by-three grid of images with the lower right element omitted. Each image is characterized by six characteristics that can vary along several patterns. Lab experiments demonstrate that the puzzles become more challenging as the number of characteristics that change increases. Further, the ability to correctly solve our puzzles is shown to be correlated with scores on the Raven Progressive Matrix test and with performance in a beauty contest game. Due to the manner in which our puzzles are constructed, there are a large number of unique puzzles that can be generated for use in economics experiments using software described in the paper. Thus our puzzles are well suited for use as an alternative method to assess the cognitive ability of respondents and for use as a real effort task with multiple levels of cognitive difficulty.