An introduction to six early Islamic geometric methodologies that were used to create many two-dimensional geometric surface designs that appear in windows, and on doors, walls, domes and minbars. These are reconstructions based on analysis and research of methodologies developed during the early years of Islam - particularly during Abbasid Caliphate (750–1258CE in Baghdad and 1261-1517 CE in Cairo) and also during corresponding periods in Persia, Morocco, Syria and Moorish Spain. The six methodologies presented are: (i) Grids, (ii) Tessellating Polygon Subdivisions, (iii) Rays, (iv) Close-Packed Circles, (v) Nesting Polygons and (vi) Modular Tiles. This paper also puts forward the idea that surface designs generated by these methods were not always intended to be purely decorational—they may have had meaning according to the logic of their design methodologies, their symbolic values, their ‘perceptual’ qualities and, possibly, their numeric values.