Overlapping instructions were used in some 8 bit microcomputers to fit code into a small memory. For instance, Apple II cards have a 256 byte window for a tiny I/O driver (the address of that window being slot-position-dependent, so the code has to be relocatable: plug the hardware into a different slot and the code moves.) Some cards use overlapping instructions in order to fit this constraint. (Cards can also provide a 2048 byte ROM. However, that was mapped to a fixed memory location shared by all the slots. Before anything jumps there, it has to ensure that the correct slot's code is currently selected for visibility.)
Interestingly, in nature there are some viruses which similarly have overlapping sequences in their DNA. That is to say, one entry point codes for a protein and then another entry point codes for another, and the sequences overlap.
Interestingly, in nature there are some viruses which similarly have overlapping sequences in their DNA. That is to say, one entry point codes for a protein and then another entry point codes for another, and the sequences overlap.