Drag the aliens from the containers to the scale arms.
The display shows which side is heavier. It?s balanced when the yellow spot is in middle.
The goal is to balance every scales.
Advanced: If a scale is under an arm, then the weight on the arm is equal with the sum of the weight of the aliens on the scale under the arm (and the alien on the arm * distance from its scale). This weight (on the arm), independence from the position of the aliens on the lower scale.