PIE Controls from the unique and awesome Paranoid ROMs, have migrated their way over to the CyanogenMod 10.1 builds. It makes sense for the CM team to incorporate this distinct feature in their ROMs. I think PIE Controls are pretty fantastic. Helps add to that whole multi-tasking feature we all love, and does so in way where the effect mimics technology that we have seen in movies.
The CM team just posted on their G+ page that they decided to implement PIE Controls within their new 10.1 builds. This is all thanks to their contributor named Jens Doll, who brought the code over to CM. On the G+ post, they mention that the code for PIE should further expand and enhance the CM builds, and they are excited for more to come. They mention too, that with expanded desktop, the PIE Controls bring the element of navigation keys without having the keys on your screen at all. The PIE Controls should be merged with the builds they start releasing from here on out, so keep a lookout. Let us know if you have already gotten it.
Source: CyanogenMod G+