Floor of the science block, the

As certain people know, having dropped large masses on it, it is not as solid as it looks. It does in fact break up, leaving a problem for those who have broken it. In cases such as these, Step 1. Find as many bits of tile a possible. Step 2. Fill the hole with these pieces. Step 3. Strategically place a stool leg over the offending place, and do not draw attention to it in any way, for at least 20 years.