Momo Nine
Your backtest is lying to you — build the 40-line Python bot that proves it
A Sunday pandas tutorial on the three ways a backtest fools you — lookahead, survivorship, overfitting — and the one-line fix every builder's model needs.
The missing-semicolon game is a clash-detection drill wearing a lab coat
A browser game hides one missing semicolon in 187,421 lines — and accidentally teaches BIM coordinators why open, greppable IFC beats lossless every time.
Your LLM never reads your IFC — it reads tokens, and IFC is the worst case
An IFC line costs ~31.6 tokens at 2.33 chars/token — 2.2× English. Measure it with tiktoken, and the "AI is bad at numbers" folklore becomes engineering.
Who pays for the robot's mistake? Reinforcement learning, from the cliff to the boiler room
From Sutton & Barto's Cliff Walking to BOPTEST and DeepMind's data-centre cooling - why RL's real question is who absorbs the cost of the agent's mistake.
The City That Publishes Its Own Bones: Mining Zürich's Open Data From a BIM Desk
Zürich publishes its civic data free on CKAN. Here is how a BIM or Grasshopper office pulls parcels, zoning and vacancy figures with ten lines of Python.
buildingSMART Certification in 2026: worth it — or just learn to read the file?
Is the buildingSMART Professional Certification worth it in 2026? A Swiss cred-eval — plus how to actually learn IFC 4.3 with IfcOpenShell in an afternoon.
Grasshopper from Zero: Your First 90-Minute Jump into Grasshopper 2
Grasshopper 2 beta adds inbuilt loops and a play/stop timer. A 90-minute first jump: slider, Series, point grid, one line of GhPython. Start tonight in Rhino 8.
Meta Switched Off Its Worlds in June. Nobody Could Export Them — Now Read Your BIM Contract
Meta removed Horizon Worlds from Quest on 15 June 2026 and community worlds were never exported — $88B of Reality Labs losses later. What AEC teams should demand about open formats before signing.
Pigeon Puts the Wait Back In — What a Slow Messaging App Knows About Your Model
Pigeon sells deliberate latency; DTN and IFC prove your model was always delayed mail. Read the IfcOwnerHistory postmark before the site trusts the file.
Graph engineering for the BIM desk: build your clash-check as a state machine
LangGraph turns clash-detection into an auditable state machine. A PAZ Academy hands-on tutorial: build a cyclic clash-check graph, route severity, keep humans in the loop.
