A regular hexagon has all sides the same length and all internal angles are 120°.
Bee's use the hexagon in their hives because it allows the most efficient use of space. Circles in a grid create spaces, and no polygon with more than six sides will be interlocking.
This is the patio that I am currently building at my house. It is in multiples of 8 - 16'x 16' with an 8' diameter octagon. When it is complete the cut out spaces will have planters with a bench spanning it and a 10' tall metal circle on wooden posts over the top.