Confused about PCIE slots and multi-GPU support

[dumpyourboss.main]

I'm confused about PCIE expansion slots and multi-GPU support. The Gigabyte Z370P D3 supports AMD Quad-GPU CrossFireX. Doesn't that mean you can install 4 videocards? The specs of the expansion slots are:
1 x PCI Express x16 slot, running at x16 (PCIEX16)
2 x PCI Express x16 slots, running at x4 (PCIEX4_1/PCIEX4_2)
3 x PCI Express x1 slots

According to the above specs, there are 3 PCIE x16 slots, 2 running at X4. So how can it have quad-GPU support?
Read the board's specs here:
https://www.gigabyte.com/us/Motherboard/Z370P-D3-rev-10#sp
On the Specification page, scroll down a little to "Expansion Slots" and "Multi-Graphics Technology". Thanks.

 

[clutchc]

I don't know where they get the quad card statement from, with only 3 x PCIe x16 slots, unless they are counting a 4th (skinny) card in an x1 slot. I see 3 cards total, with the last 2 running at x4 lanes each.