The goal is for the mid point of the hand to be positioned on the white circle.
Fitness is measured over 28 defined target points (28 trials).
For each trial we calculate the mean distance from target across all timesteps, early timesteps are weighted down to de-emphasise speed approaching target and emphasise accuracy of targetting.
Final fitness is the square of each trial's mean distance value. This emphasises improving the worst trials over better ones (classic reduction of squared error)