This weeks pattern was not inspired by a manhole but by another road feature - the concrete where to cross the road. I assume it has been architecturally designed so that we notice a textural change in the pavement when crossing the road and for grip. I like this bobble pattern as it is smaller than the retro 60s big bobbles you see in crochet books from that time.
Make a multiple of 5 plus 2.
Row 1: 1 dc/sc in 2nd ch from hook, 3 dc/sc in each of the next ch, 5 ch followed by 1 dc/sc in next ch (to make the bobble) continue with 3 dc/sc followed by a booble untill the end, turn.
Row infinity and beyond: Repeat row 1 and 2 until you have achieved right height.