Convex polyhedra are polyhedra which are more or less ball shaped. This might sometimes hard to imagine if you consider a pyramid to be a convex polyhedron. Another definition might be that all dihedral angles are less than 180 degrees (although this definition is not entirely true). You can check if a polyhedron is convex to connect two vertexes of the polyhedron with a string. If this string is always running over the surface of the polyhedron (regardless the vertexes used), then this sphere is convex. If the string is running through the air (as in a star) than the polyhedron is non-convex. 

Most puzzles described on this website are related to convex polyhedra. Therefore this is an important topic if you are working with puzzles. Furthermore are most non-convex polyhedra related to the convex polyhedra.

	4 Families Here you can find the basic of polyhedra. Four families will be described: the Rhombic, Platonic, Archimedic and Catalan Polyhedra. It will also be shown that there will be four families in another way: the trigonal, tetragonal, pentagonal and hexagonal family.
	Half-Regular Polyhedra In this chapter other half-regular polyhedra will be described. You can think of pyramids, prisms, anti prisms, double pyramids and trapezoids
	Johnson Polyhedra Norman Johnson has described all possible convex polyhedra build out of regular polygons. Next to the Platonic and Archimedic solids and the prisms he has found 77 other polyhedra who are now known by the name Johnson polyhedra
	Deeper into Irregularity The number of convex polyhedra is of course endless. Based upon the regular and half regular polyhedra it is possible to make more polyhedra which can be quite useful as basis for puzzles.
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