Basically the Sam as the front if you interlock the blocks.
The Beltis Avondale blocks (#1004-959-488) that I've purchased summer 2020 have been a medium, sometimes darker, gray. About 5% of the blocks have chips or imperfections that make them less desirable for use. I've easily returned and exchanged these at the local store.
Yes, I ordered 175 of these and Home Depot delivered the next day. Right product at the right price with a reasonable delivery cost.