The Twist serve and its TWO Axis of spin. Debate Please

[paulfreda]

SpiralSpin

what is this spiral spin?

I thought there was only topspin,sidespin,backspin, and flat and you can mix topspin with slice to get topspin slice ect and same goes for twist serve and stuff.but spiral spin???

Axis of rotation for .........
Topspin; Horizontal pointing to a side fence
Sidespin; Vertical
Spiral Spin; Horizontal pointing to the target

Hope that helps