Algodoo

Unusual method, but it works! Good job.

You could delete "e.this." and replace ":=" with "=" in your code.

Code in "e.this._time >= 5" never executes.

The following arm code will also work:
(e)=>{
_time = _time + _interval;
_time >= 5 ? {
_time = 0
} : {};
_time >= 1 ? {
ra := [[-1.5, 2.75], [-1.25, 3.5], [-1.0, 3.75], [-0.5, 3.75]];
vel = (ra(math.toInt(_time - 1.0)) - pos) * _animspeed}:{};
}

it looks good 6.7/10

10/10