CON_2x2, Synplicity's High-performance ASIC Prototyping System adds a bus that connects 4 adjacent connectors. By removing 0-ohm resistors the bus can be split in two diagonal buses. The primary use is for adding diagonal connections between FPGAs on the HAPS board, or for creating a global 4-FPGA bus. It’s typically placed on the 4 middle connectors on HAPS.