I have a need to take a square pulse of 0V/+5V and about 5-10ms duration, and stretch it out long enough to flash a LED brightly enough to be visible indoors under "ordinary" lighting conditions.
I currently only have op-amps on the board and would rather not add any logic ICs to do this. So using low-speed op amps and discretes would be fine. The pulse source into the stretcher would be low impedance.
An optional feature would be to have the "stretch" duration decrease the more rapidly pulses are coming into the circuit. But that is not a requirement if it needs significant complexity.