Draw a straight line
Draw a perpendicular line
Make 4 right-angled triangles from the two axes
From vertex B, draw one fourth of the contour of the arena.
From vertex C, draw one fourth of the contour of the arena.
From vertex D, draw one fourth of the contour of the arena.
From vertex A, draw the axes of the radiating walls.
From vertex D, draw the axes of the radiating walls.
You have drawn the floor plan of the amphitheater!