What is the difference between a PCIe x1, x4, and x16 slot

Tip to Use a Dremel to Cut Open a PCIe x1 Slot x1 pcie slot If you take a x1 connector and use a saw to open the end of the slot then you can physically connect a larger card and it should work I know at x16pciexp slot Supports PCIe motherboards and is backward compatible with PCIe and PCIe Also supports PCIe x1 bus slot The NVMe PCIe card

x16 slot SATA card for PCIe x1 slot with 8 ports Bizarro