Using the interactivity, can you make a regular hexagon from yellow triangles the same size as a regular hexagon made from green triangles ?

If the yellow equilateral triangle is taken as the unit for area, what size is the hole ?

Which of these triangular jigsaws are impossible to finish?

Can you work out where the blue-and-red brick roads end?

If you think that mathematical proof is really clearcut and universal then you should read this article.

Solve the equations to identify the clue numbers in this Sudoku problem.