So I had something happen with a ball at a friends house when I was about 910 my friend was 2 years older so 1112 . I ' ve always chalked it up to my friend winding me up but I seriously can ' t recall him having chance to set it up . My friends Dad was at work and his Mum had popped out somewhere or other . The upstairs hallway was a U shape upside down with the stairs running up the middle . It ' s hard to explain so here ' s a floor plan from a house that ' s currently for sale on the same street . That ' s the upstairsI was sat at the top of the stairs , my friend at the bottom . We were rolling a ball down the stairs bouncing it down . It was my friends dogs ball . The dog wasn ' t allowed in most of the house as it was blind and would crash into everything . The dog was only ever in the kitchen , utility and the garden . After a while we decided to watch TV and I rolled the ball into Bedroom 2 so that it wasn ' t lying around in the hallway or at the top of the stairs . A good while later At least half an hour my friend and I hear the thud , thud , thud , thud of the ball bouncing down the stairs . We knew exactly what the sound was , as we ' d been making it ourselves earlier that day . We popped our heads around the door to see the ball at the bottom of the stairs . My friend hadn ' t left the room for ages so if he set it up , it was on some elaborate timer . The dog wasn ' t in the house , he certainly wasn ' t upstairs . Nobody else was home either . The ball was too large to fit between the gaps in the spindles at the top of the stairs . Even if the floor wasn ' t level , the ball would have had to make a U turn to get around the spindles and onto the actual staircase I believe in the US you guys call spindles BalustersSomehow this ball rolled 67 feet down a hall , Turned to the left and went in the complete opposite direction to roll over the first step on the staircase . I always look for a reasonable explanation , it ' s half the reason I read the posts here . They get my brain working . With this one , I can think of nothing other then my friend playing a prank on me . He didn ' t leave the room the entire time . So if it was him , he set it up previously and somehow delayed the ball rolling down the stairs for at least half an hour .