The surface on which the tower is resting is pushing back up. Small air movements are also adding forces from the side. Building a wide base at the bottom will distribute the weight over a wider area and make the tower more stable if it is pushed sideways by the air
Answers & Comments
at_answer_text_other
The surface on which the tower is resting is pushing back up. Small air movements are also adding forces from the side. Building a wide base at the bottom will distribute the weight over a wider area and make the tower more stable if it is pushed sideways by the air
at_explanation_text_other