There are two products that do what you want. One is plastic, one
is a CMU block product.
Look up "sod block" or scroll down to the bottom of this page for
There is a plastic version:
We used the plastic one once, but did not have good luck standing
up to buses and trucks. The CMU version we used was full 8" deep,
but worked well. The same results could be had by turning regular
CMU upside down and spacing them out.
Keep the whole world singing . . . .
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