First, the buildings are limited in total height. The maximum height is equal to the width of the street (including sidewalk). The narrowest Avenues (like Queen Street) are 20 m wide and allow 20 m high buildings (usually 6 storeys); the widest Avenues (like Sheppard Avenue) are 36 m wide and allow a 36 m high buildings (usually 11 storeys).
Second, buildings are required to fit within 45 degree āangular planesā at their front and back, measured from predefined points. The impact of these envelopes is that the building rises straight for a few storeys at the front and at the back, and the floors above are stepping back.