Your job is to compose a molecule using all atoms.
Start composing by holding down left mouse button on one of atoms. Move your mouse to another atom to join them.
You have six types of atoms and each type has its own valency from 1 to 6. The level is complete when all valencies of each atom are used. The numbers near atoms show the number of used valencies and full valency as well.
You can change type of atom by clicking it (remember, it costs one point).
