Made me smile. Team Jacob

What a great resource. Thank you

They did. And in a perfectly valid way.

Better to not announce to the world "Hey everyone! Whaddya think?" If you can only tolerate approving answers. No one made them post a bad version of a one-liner that could already be googled up from 20 other examples already out there and better engineered.

This sort of send-up is actually perfectly on target, and frankly actaully light hearted.

Everyone posting critiques like this and like my own, knows full well that they have their own excrable works of art out there. We've all been figurative 7 year olds and made terrible crayon drawing programs, and even been ignorantly and adorably proud of them at the time.

Better to just laugh at the good joke.

"Goodbye Galaxy" was perfect. I still remember the place where Commander Keen showed his butt.

i knew none of these :( never made it past the ice level or the big pyramid shaped one.

Impressive to see how many Stolpersteine are out there. I never saw/recognized one on my own even though I walk around a lot in areas with a high density of them.

I think it's almost like Baader-Meinhof Phenomenon. When I randomly recognized the first one, I suddenly realized there were many more I would pass everyday but had never noticed.

I didn't know of them until after I had moved to Hamburg, where there are quite a few. My SO showed them to me and told me the background.

I was flabbergasted. Being very interested in history, having studied history at university and never before having heard of them was quite frankly disconcerting for me back then.

Since I nearly always stumble (as intended) as it is a visual pattern I now instantly recognize.

That's pretty clever and impressive.

That's some serious dedication. But looks phenomenal.

I bet that was done by JGC

Great visualization. Might become my new screensaver.

One could even feed the hash back into itself to get a different result each time

how long would the cycle last before it starts repeating?

On the order of 2^256 steps, if SHA-256 behaves randomly, since the largest cycle in a random permutation on N elements has expected length ~ 0.62 * N.

SHA-256 is not a permutation; the expected cycle length is ~2^128. It's how collisions are (generically) found.

Pigeonhole principle?

Each new output value i can collide with output 1, 2, ..., i-1. So the collision probability of iteration i is (i-1)/2^256. Adding all of the iterations up you have 1/2^256 + 2/2^256 + ... + (i-1)/2^256 = 0.5 i (i-1)/2^256 which approaches 1/2 as you get to 2^128.

In reality you use some variant of Rho which does not store every previous value but uses something like Floyd's cycle detection or distinguished points and requires minimal storage, at the cost of some extra hash computations but still on the order of 2^128.

This situation calls for Birthday paradox, not pigeon hole.

Then wouldn't that be 0.62*2^256, closer to 2^255 ? Not that it makes a notable difference: at 1 fs per step (1000 GHz, or 1 TH/s), that would take about 4.5e65 years to happen. The universe is only about 1e10 years old...

It would be at least that, with a smaller contribution to the expectation from smaller cycles. That's why I said "on the order of", i.e. not much smaller.