Optical illusions are a fun and interesting way to challenge our brains and sharpen our observation skills. Sometimes, what we see at first glance is not the complete picture. There are hidden within ...

Arc length is a fraction of circumference. Area of a sector is a fractions of the area of a circle. Both can be calculated using the angle at the centre and the diameter or radius. Practice circle ...

Looking at mosques, madrasas, palaces and tombs from the 8th-19th centuries, Eric Broug analyzes and explains Islamic geometric designs in their historical and physical context. Chapters cover the ...