These applications are freeware and may still be downloaded from MIT's Hyperarchive. All run on PowerMacs, OS 7.0 to 9.0, and will run under OS X in Classic. Under Lion, on an Intel Mac, they have become unusable. For an OS X-native application that encompasses these three programs and does far, far more, please visit my commercial app site for Synthimax.
Escape Fractals is a small program that implements an algorithm described by Clifford Pickover in an article in "Computers and Graphics", Mar/Apr 1995.
Halley Maps draws (big surprise) Halley maps, as described by Clifford Pickover in his book "Computers, Pattern, Chaos and Beauty."
Dynamical Systems is a program that creates pictures of various dynamical systems. It draws on ideas from (again) Clifford Pickover.