Ok ... you can type the manuscript with chalk, without coloring it first, just draw it directly, because the surface of the manhole cover is not absorbent, so don't add too much water to the gouache pigment. When washing, the broom will fall off as soon as it is washed with water. This urban management is difficult to catch, depending on where the manhole cover is. Generally, there is a management park in the park, so it's hard to say on the roadside, depending on where it is.