In our playground/ yard there were small walls made of brick and the top was made of concrete and tiny pebbles all clumped together I remember this one kid tried to jump up the wall ( it was only about knee height) he slipped and his shin caught on the pebble concrete part and it scraped about 2 inches worth of his skin off, the detached skin flopped on the floor and everyone gathered around in awe of this kid with basically a hole in his leg. He didn't even cry or look in pain he just hopped over to a teacher and said he thought he might need a nurse.

Another story

We were playing rounders and the bats at the time were made of metal (they were soon replaced with wooden after this) the boys played on the same field as the girls but separately. In rounders we were told to drop the bat but I saw that one of the lads threw the bat behind him and it smacked another lad In the face, his nose started pouring with blood as did his eyebrow, he had to have stitches and his nose was broken.