Supermicro proprietary PCI-E slot adapter riser cards or cables?

Supermicro proprietary PCI-E slot adapter riser cards or cables? pcie x32 slot PCI Express® specification has served as the de facto interconnect of choice for nearly two decades The PCIe specification doubles the pcie 30 in 40 slot Unlike the much older ISA and PCI standards for card slots, the newer PCIe standard can be sized for efficient use of system resources, and is

pcie 30 in 40 slot PCIe cards can always operate in PCIe slots with the same or more lanes than the card For example, an x8 card can operate in a slot with x8, x16, or x32 lanes

pcie 20 x16 slot PCIe cards can always operate in PCIe slots with the same or more lanes than the card For example, an x8 card can operate in a slot with x8, x16, or x32 lanes  Would i be right in thinking that a x32 can only slot one video card? I ask because i am unfamiliar with the PCI-E X32 slots