What is their proper name, so I can call around and ask?
Not sure what the proper name is. Call a few block suppliers or search
for "green driveways".
I have seen a few boat parking space locally that were built from your
standard old 8x8x16 blocks sit on a gravel base and filled with dirt. A
herringbone patter looks better that just placing them in rows.
They seem to call them many different names:
Open Paving blocks
Permeable Paving Units
Open cell concrete blocks