Around 1986 a new AI company Cognitive Applications Ltd., collaborated with members of Sussex university to produce a variant of Pop-11 called AlphaPop running on Apple Mac computers, with integrated graphics. This was used for a number of commercial projects, as well as being used for teaching AI programming in several universities. The fact that it was implemented in an early dialect of C, using an idiosyncratic compiler made it very hard to maintain and upgrade to new versions of the Mac operating system. In addition to this, AlphaPop was not "32-bit clean" due to the use of high address bits as "tag bits" to signify the type of objects, which was incompatible with the use of memory above 8Mb on later Macintoshes.