The cards were an insert set to Upper Deck's 2009 series one. They obviously borrow from Topps' 1975 design. In addition to the regular cards, there were parallel minis. This borrows on what Topps did in 1975. However, these are OPC cards and OPC didn't put out a mini set in 1975...so why did Upper Deck add minis?
Here's what the regular cards and minis looks like together.
Upper Deck was really pushing the OPC name in 2009 because in June they came out with a complete set of OPC cards, a 600 card series.
This time they has a slight Topps 1976 look. The set was originally supposed to mimic the 1971 Topps set. I think this was when Upper Deck was claiming that since they owned the OPC brand name, and since OPC put out cards licensed by Topps in 1971, that gave UD the right to copy use the design. I also believe that Topps brought a suit to stop Upper Deck. It seems that at the time Upper Deck was trying to drag Topps into court as often as possible. It was pretty futile on their part, since Topps has prevailed in every case.
Stir up the hornets nest enough times and your going to get stung. Upper Deck has been pretty much stung into irrelevance.