Interchained × Bitcoin — Difficulty, Side by Side

An interactive booth that puts a Bitcoin-style chain next to Interchained (ITC) and lets the public feel the single biggest engineering difference: how each chain handles a change in mining power. Yank the hashrate and watch Interchained's DarkGravityWave3-Nova re-target every block while Bitcoin's 2,016-block epoch sits frozen for weeks. Everything runs 100% client-side — real SHA-256 and a faithful port of the real retarget logic. No node, no backend, no install.

This is a sibling to the Playground Lab. The Playground is the hands-on "mine it yourself" lab; the DAA Showcase is the guided BTC | ITC journey built on the same real engine. They link to each other but stand alone.

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The journey

A self-driven scroll. Each beat renders Bitcoin (orange) and Interchained (cyan) side by side.

1. Hero — "Bitcoin walked. Interchained runs." Two identity cards lay out the shared DNA and the diverging spec: 10 min vs 60 s blocks, 2,016-block epochs vs every-block retargeting, SHA-256 vs Yespower→SHA-256.
2. The shared foundation. A live, genuine SHA-256 miner grinds nonces until the digest clears a target — proof that both chains rest on the same hard problem. Interchained only changes the rules around it.
3. The centerpiece — Difficulty. The DAA station (see below). Yank the hashrate, fire preset shocks, and watch the two responses diverge block-by-block on a shared chart.
4. Height-based migration. Scrub the block height across the fork and watch the proof-of-work algorithm hand off from Yespower to SHA-256 in lockstep, with no flag-day coordination.
5. By the numbers. The spec sheet, BTC vs ITC, row by row.
6. The energy question. The eco-grants framing: proof-of-work without the warehouse.
7. Why ITC. The "so what" close — resilience under stress is the point.

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The centerpiece: the DAA station

This is the reason the booth exists. One shared pool of mining power drives two real retarget algorithms at once.

What the visitor can do

• Yank the hashrate on a log slider (0.1× → 20×) and watch difficulty respond.
• Fire preset shocks: "Whale plugs in 10×" and "Half the miners leave."
• Fast-forward to Bitcoin's retarget — honestly steps the sim until Bitcoin's 2,016-block epoch finally ends, so you can see how long "until it can react" really is.
• Read both chains live: difficulty, actual vs target block time (color-coded), and — for Bitcoin — a meter counting down the blocks/days until its next possible adjustment.
• Follow the lesson: five guided steps that auto-advance with the action, so the education coincides with the tinkering.
• Cross the PoW fork on the migration scrubber.

The takeaway lands on its own: shock the network and Interchained is back on its 60-second target within ~12–24 blocks, while Bitcoin is stuck off-target for the rest of its epoch — roughly two weeks — and can only move 4× when it finally does.

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What's real vs. modeled

Being precise about this matters — the booth is teaching the public.

Genuinely real

• dgwNova() in daa-engine.js is a faithful, branch-for-branch JavaScript port of Interchained's C++ retarget: the 12/24-block window, the recursive weighted average of past targets, actualTimespan / targetTimespan, the height-aware clamps, the emergency trigger evaluated before clamping, the rolling-median solve time, the graceful decay (multiplier^0.45, capped at 2.0), the median smoothing of the difficulty window, and the asymmetric decay-from-baseline final target with its powLimit cap.
• Bitcoin's side is the real 2,016-block epoch formula with the 4× per-epoch clamp.
• The hashrate ↔ difficulty ↔ block-time relationship is the genuine physics: at equilibrium, difficulty settles at exactly the hashrate multiplier.
• The Foundation miner computes real SHA-256 live (and the full Playground mines real proof-of-work blocks).

Modeled, by necessity

• Block solve times are drawn from the correct exponential distribution, not mined. You can't reproduce a network-scale "10× hashrate" swing on one laptop, so the arrival of blocks is simulated while the decisions made about them are the real algorithm. Variance is gently damped (mean-preserving) so the teaching chart stays legible.
• Targets are JavaScript floats, not the 256-bit nBits fixed-point encoding — the logic is faithful, the bit-packing is dropped because it has no effect on the behavior being taught.
• Heights and parameters (fork at #200, 60 s spacing) are chosen for a legible story, not pulled from mainnet.

Nothing on screen is a fake number: every difficulty value, block time, and countdown is computed by the real algorithms from the live state.

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How it's built

Layered on the existing Interchained design system and the Playground's real engine.

Engine — showcase/daa-engine.js

Plain JS on window.DAA. No framework.

• dgwNova(blocks, params, nextHeight) — the faithful DGW3-Nova port; returns the next target.
• makeSim({ hashrate, jitter }) — the dual-chain simulator. step() mines one ITC block and advances Bitcoin by the same elapsed seconds; view() returns the live readout slice; setHashrate() applies a shock.
• powInfoForHeight(h) / isPostSha256Fork(h) — the height-based Yespower→SHA-256 fork.
• Self-tests its equilibrium on load (block time settles near the 60 s target).

UI (React + Babel, in-browser)

• showcase/daa-lab.jsx — the DAA station, the dual difficulty chart (SVG), the guided steps, and the migration scrubber. On window.DAALab.
• showcase/sc-sections.jsx — every narrative beat: hero, live-SHA-256 Foundation, the DAA wrapper, migration, by-the-numbers, eco, why-ITC, footer. On window.SC.
• showcase/sc-app.jsx — composes the journey, scroll-spy nav, the top progress rail, and the Tweaks panel.
• showcase/sc-styles.css — the booth layer (BTC|ITC dual-accent language, control deck, chart, steps) over explainer/styles.css + playground/pg-styles.css.
• Reuses playground/engine.js (real SHA-256), playground/pg-shared.jsx, and playground/tweaks-panel.jsx.

Tweaks

Open the Tweaks panel to adjust, live:

• Sim & animation speed (0.5×–3×).
• Interchained accent and Bitcoin accent colors.

Running it

Open ITC Showcase.html. It loads React, Babel, and Lucide from CDN; everything else is local. Because it transpiles JSX in the browser, the first paint takes a moment, and on a flaky connection a script can occasionally fail to load (a refresh fixes it). For a fully offline, single-file version, the project can be bundled into one self-contained HTML file.

Notes

• Everything is 100% client-side. There is no network, no wallet, and no real asset — it's a teaching tool. Bitcoin is referenced factually for comparison, not cloned.
• The booth is designed for self-driven scrolling and is mobile-ready; the DAA station pauses its loop when scrolled off-screen to save CPU.
• Not investment advice.