ATOMINO

From the manual:

In ATOMINO your task is to combine atoms into 
molecules...Now, we all know that atoms are normally 
on the small side, and they appear to spend most of 
their time aimlessly flying around, a fact that 
complicates their handling. Therefore, in ATOMINO, 
we have objects which look like atoms, smell like 
atoms, and, just like real atoms, have the capability 
of combining with one another. They are, to all 
intents and purposes, atoms - apart from the size 
factor, of course.

The atoms have a valance (look it up) of one to four, 
i.e. they can combine with one, two, three or even 
four other atoms.

Let me explain: imagine these atoms as small, naked, 
spherical, swarming beings, each armed with up to 
four hands. When two swarmers shake hands (when two 
atoms combine), each now has one less free hand 
(henceforth, free hands will be called free 
combinations, otherwise, this manual may begin to 
sound kind of silly...)

A complete molecule is defined simply as a structure 
of atoms in which there are no more free combinations.

WARNING! For demonstration purposes only, this 
packaging contains some sample atoms in original size 
(find 'em if you can!).