Anthrobot Lenia
Soft, continuous creatures made of two kinds of mass: body (blue) and cilia (magenta). Local rules decide where the cilia gather; wherever they sit on a creature’s rim, they push along it. Nobody programmed how these creatures move.
How the creatures work, and what to try
The creature lives on a small grid that wraps around at the edges. Every point holds some body mass (blue) and some cilia mass (magenta), and a few smooth rules about each point’s neighborhood decide where that mass flows. Mass is never created or destroyed, only moved, so a creature keeps its substance. Wherever cilia sit on the creature’s rim, they push along it: a ring of cilia spins the creature, a lopsided patch makes it travel. Nothing says how it should move; that comes from where the rules put the cilia.
The creatures in the gallery were found by a search that tried 1,280 sets of rules and kept those that hold together and move. Each is grouped by how it moved while the search watched it: linear, circler, wiggler, spinner or drifter. The line under the view measures the live creature the same way, over its last few hundred steps.
The controls. Click to drop new mass; drag across a creature to cut it. “Tweak it” changes the rules live: how hard the cilia push, the center and width of the growth rule, and the size of the neighborhood each point senses. Mutate nudges every rule a little, Reset returns to the creature as found, and Restart starts it again from its snapshot. “Show cilia thrust” draws arrows where the cilia push. The grid size changes the world the creature lives in; the search used the smallest.
Things to try. Pick a spinner, turn on the thrust arrows and watch them circulate around the body. Raise the cilia thrust and see it spin faster, or set it to zero to see how much of its motion came from the cilia. Cut a creature in half: does it heal, split or dissolve? Watch the live reading for a while: creatures speed up, slow down and change style, so the label can change. Then look at the motility chart below the view, where every creature found sits on one continuum of speed and spin.
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Conclusion
Real anthrobots are described as falling into motility classes: circlers, straight-line movers and wigglers. We asked whether such classes would appear on their own in soft creatures whose only way to move is cilia pushing along their rim. The behaviors do appear, every one of them: among 59 creatures that held together, a search found straight movers, circlers, wigglers, spinners and drifters. But they don’t form separate classes. Grouping the creatures by how they move finds only a loose divide between those that stay put and those that travel, and the grouping is about as weak whether it looks for two kinds or six. Individual creatures also change style over time, speeding up, slowing down and switching from one behavior to another. So in this model, body shape and where the cilia sit are enough to produce each kind of motion, but not to sort creatures into distinct kinds. If real anthrobots do form sharp classes, something this model leaves out would have to sharpen them. The search was a small one and the comparison with real anthrobots is qualitative, so this is a first look, not a verdict.
The science
Lenia is a continuous cellular automaton: each point on a grid holds some mass, and smooth, ring-shaped rules about its neighborhood decide how that mass changes. Flow-Lenia makes the mass move instead of appearing and vanishing, so creatures keep their substance. Here a second kind of mass, cilia, pushes along the body’s edge, the way the beating hairs on an anthrobot’s surface propel it.
What’s real
- Anthrobots assemble themselves from adult human airway cells and swim with cilia on their surface.
- Their motility (circling, straight, wiggling) relates to their shape and where their cilia are.
- Mass conservation and local rules are standard tools for modeling self-organizing tissue.
What’s simplified
- Lenia is an abstract field, not cells: “body” and “cilia” are two kinds of mass, not tissues.
- Cilia thrust is a single rule (push along the rim), not real ciliary beating in fluid.
- The comparison with real anthrobots is qualitative; nothing here is fitted to measured data.
Sources
- Gumuskaya et al., “Motile living biobots self-construct from adult human somatic progenitor seed cells,” Advanced Science (2023)
- Chan, “Lenia: Biology of Artificial Life,” Complex Systems (2019)
- Plantec et al., “Flow-Lenia: Towards open-ended evolution in cellular automata through mass conservation and parameter localization” (2023)
- Inria Flowers team, “Sensorimotor agency in cellular automata”