Kalidiscope effect

Friends in the Photoshop Family:

I stumbled onto a set of steps that allowed me to merge two images and then (magically) created a new format that would spin the two images like a kalidicope effect. The images tumbled, turned, and would spin. Fascinating! I tried to do it the next day and couldn't remember how I created this magic window.

I did NOT cut the images. I did NOT use mirror effects. I simply put one image on top of the image in the document screen and then . . .  and then . . . I don't remember what I did next. 

What is this effect called? And, where can I learn how to repeat it. 

Thanks in advance.

Phyllis Davis