# Islamic Geometry: A Window from Ibn Tulun Masjid

Since we started with the first geometric pattern that I learned, I thought we’d jump right on over to the most recently one I’ve draw. This pattern is from a window grille in the Mosque of Ibn Tulun, the oldest mosque in Egypt and the oldest surviving mosque in Africa. We drew this with William Charles Riding and the Prince Foundation School of Traditional Arts.

It’s also another a six-fold pattern with a central star. This time, though, the angles in the star aren’t 60º, so it requires a few extra lines.

1. Divide the circle into twelve. Draw a horizon line and a mother circle with a radius on the line. Add circles with the same radius on the east and west. Add four more circles of the radius at the intersections. Draw a vertical bisector. Add a north and south circle where the vertical bisector intersects the mother circle. Finally, number each point on the mother circe like a clock.

2. Two triangles. Draw a dynamic hexagon at the even points. Draw a triangle facing up at 12-4-8 and a triangle facing down at 2-6-10.

3. Three squares. Draw three squares at 12-3-6-9, 1-4-7-10, and 2-5-8-11.

4. One star. Draw one star from 12-5-10-3-8-1-6-11-4-9-2-7-12. Another way to do this is to connect 12 to 5 and 7, then do the same at points 3, 6, and 9. Then connect the loose ends.

5. “Anglefish”. Draw six “anglefish” at the odd points. Notice that the nose is at the points, the tail starts at the green intersection, and the tail and fins end at the red line.

6. Bisectors. Add in four more bisectors. These go from 1-7, 2-8, 4-10, 5-11. 12-6 and 3-9 are already drawn in gray.

7. Small star. Connect the tips of the tails of the anglefish along the blue lines. The connections “bend” where the dark blue lines intersect.

8. Large star. Connect the tips of the fins of the anglefish. Draw lines parallel to the light blue lines that you just made. These lines pass through the light blue and red intersection and “bend” at the bisectors.

9. Finish. Draw in your final lines. You should have twelve perfect squares – one at each point of the large and small stars.

You can tessellate the pattern by creating a little three-lead clover out of the squares on the corner or by overlapping the squares.

If can’t tessellate for infinity, the centers of the main stars are good cropping points to make.

This is also a great pattern for playing with color saturation.