Yes, this was the cheap Lego knockoff from the 1970’s and 1980’s. I can still remember that giant white box of sturdy cardboard, and my confusion about what to do with the round pieces. (Were they supposed to be wheels?)
You could buy Brix Blox at Sears. (My family got a lot of things at Sears. There was a standalone Sears department store two towns over where you could probably buy anything for your home except groceries or hardware. I suppose that stores like that were the closest thing we had in the 80’s to “big box” stores like Walmart.)
These were originally called Loc Blocs by their Japanese manufacturer; Sears rebranded them. They were absolutely generic and considerably larger, which meant there was no way they were compatible with Lego’s smaller standard pieces. It didn’t matter to me. I loved Brix Blox. When I saw Lego sets at other kids’ houses, they always looked weird and small and fancy.
It still befuddles me as an adult that Legos have such a loyal, nostalgic fan base — complete with the Lego movies and videogames. The brand’s popularity was just an 80’s phenomenon that I was never a part of. I will never understand, for example, the need for the “The Lego Batman Movie,” even though it has been explained to me. To each his own, I guess.