▲It Takes Two Neurons to Ride a Bicycle(fermatslibrary.com)
43 points by malshe 4 days ago | 6 comments
▲ebhn 1 hour ago
Nice article, but the methods they used seem more like they just hand wrote a function for the task and called the function neurons based on how it was implemented. It is encouraging though that a simple network can be found for a complicated task like this, kind of like the Tiny Recursive Model that came out last year.
▲klas_segeljakt 2 minutes ago
What about drawing a pelican riding a bicycle?
▲fintler 1 hour ago
I had fun reading this. Thanks for sharing.

With dendritic compartments, this seems like a waste of a perfectly good neuron that we could productively use elsewhere. ;)

Note that a SINGLE neuron can compute nonlinear functions like XOR.

Shameless plug: If anyone is interested, I did a post a while back on how neurons can act as logic gates:

https://blog.typeobject.com/posts/2025-neural-logic-gates/

This article builds on the first and creates a half adder out of neurons:

https://blog.typeobject.com/posts/2026-timing-is-the-bit/

▲shomp 37 minutes ago
Research question: does it make sense to make a new family of logic gates using neurons? My intuition says there is a rich texture/fabric to uncover here. The best analogy on hand right now is legos: rather than 2-knotch legos [standard gates like NAND, XOR] what about some sort of new, irreducible gates that are bigger "legos"? Been a while since I played with logic gates but my intuition says there is something lurking below the surface. A new class of irreducible gates, maybe cross-connections? Like compacted multilayer gates? Think SHA-512, how certain bits feed into different layers of the "puzzle". Optimistic this thought-amalgam serves you in your continued research :)
▲fintler 10 minutes ago
Yes!

I started going down the path of building a ripple carry adder already (which seems to work fine). Then I was going to try for a full on ALU, then some sort of ISA that sits on top of it all.

I have no idea what the end result will look like if it all comes together. Hopefully I'll find some weird primitives along the way. :D

It's very hand-wavy, but I'm kinda hoping I can somehow have a machine manually constructed out of neurons that can naturally interact with one built with looser hebbian learning rules.

▲wrsh07 26 minutes ago
> The output of the first neuron is fed into the second neuron, whose outputis connected to an actuator which applies the specified amount of torque to the handlebars. As inputs to the network, we provide the desired heading θ_d, as well as the current heading θ and the degree to which the bicycle is currently leaning γ, along with their derivatives ˙θ and ˙γ.

It's somewhat important to consider the inputs, because if you want to make a classifier that can classify "inside circle vs outside circle" but the network needs to derive the nonlinearity itself, then you end up needing a more complex network

Eg on the playground^, see how many neurons you need to train a circle without using more than x1 and x2?

And yet, if you give the network x1^2 and x2^2, it can solve it with minimal additional neurons.

^ https://playground.tensorflow.org/#activation=tanh&batchSize...

▲hyperhello 1 hour ago
So can we have self-driving bicycles?
▲onesingleblast 3 minutes ago
Yes and they'll have one of those wetware computers on board
▲soupspaces 22 minutes ago
Recumbent bike with lidar? Sign me up.
▲ 59 minutes ago
▲shomp 43 minutes ago
The instability ink-lines look like a flower blooming.

Observation: 2 neurons, 2 wheels. One for each?