Casio Fx-9860 Today

Instead, the rabbit population would boom, crash, then settle into a perfect repeating cycle of seven distinct states. Every single time. Different initial conditions, same cycle.

Leo had owned the calculator since junior year of high school—secondhand, with a cracked corner on the case and a faint scratch across the “EXE” button. In class, it was just a tool: graphs, matrices, statistics. But at night, alone with a cup of instant coffee, it became something else.

He checked his code twice. No hidden constants. No forced periodicity. Just simple rules and a tiny bit of memory. And yet, the little gray calculator—CPU running at maybe 8 MHz, RAM measured in kilobytes—was showing him something that looked suspiciously like an emergent law .

He pressed , then PRGM . Ran it again. Same result. Seven states. Like a heartbeat.

Here’s a short story inspired by the graphing calculator. It was 3 a.m., and the fx-9860’s dim green LCD was the only light in the dorm room.

He had written a tiny program in the calculator’s BASIC-like language—just 47 lines. It simulated a simple ecosystem: foxes, rabbits, grass. But he’d added a twist: a variable he called “memory.” Each rabbit remembered whether the last patch of grass it visited was safe or not. Nothing complicated. But over 10,000 simulated days, something strange kept happening.