The original astable multivibrator ran from a dead CR123 primary lithium cell:
With a terminal voltage falling from barely 3 V, the LED drew about 3 mA (1 mA/div), tops, without a ballast resistor:
Hacking in a charged NP-BX1 secondary lithium cell boosted the supply to 4 V:
Which, diodes being the way they are, raised the LED current to nearly 400 mA (100 mA/div):
Somewhat to my surprise, a few weeks of abuse didn’t do any obvious damage to the LED, but I added a resistor while I was soldering up another holder:
There’s not quite enough room for a 1/8 W axial resistor, so why not blob in a surface-mount resistor?
Which cuts the current down to a mere 15 mA (10 mA/div) from a lithium battery at 4 V:
It’s still blindingly bright, but now I don’t feel bad about it.
The Smell of Molten Projects in the Morning 
Love it. Rube Goldberg would be proud.
Convincing all those spare parts to fly in formation may look easy … [grin]
Perhaps an entry for Hackaday’s Circuit Sculpture contest?
https://hackaday.io/contest/162559-circuit-sculpture-contest
The two-digit display is downright cute!
My stuff isn’t in that league … yet. [grin]