Scheme

1. Definition 2. Regular Tessellations 3. Semi-regular Tessellations 4. Non regular Tessellations 4.1. Quadrilaterals 4.2 Triangles 4.3 Hexagons 4.4 Tiling of Cairo 4.5 Concave Polygons 5. Construction of tessellations 6. Tessellations like art 7. Tessellations and mathematics
 * It looks pretty well**