At work I was asked if I knew what block was, this was refering to Allen Bradley PLC processors, and the only thing that I could think of was the older programs and processors had their programs divided up into blocks and when the program was running it would start at the first rung in Block 1 and go to the end of line rung and then to block 2 and go on this way unless there was a jump command in the block it was scanning and this jump command's rung had been satisfied and then would cause the processor to jump to another rung or block, this is if I understand it correctly, also I am pretty sure that now in the newer programs and processors it is called "Ladder" as in ladder-1, ladder-2 etc., If anyone could help me or let me know if I am wrong about how the jump command works I would be grateful.