function needs indexable variable as argument

This function needs an indexable variable as one of the arguments.

This does not work:

my_speed = speed( 1 );

To determine the speed a channel is needed (indexed by frame):

/*

This will return ( Effector2.Position[ frame ] - Effector2.Position[ frame - 1 ] ) * fps

*/

my_speed = speed( Effector2.Position );