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.

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.

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.

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.

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

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).

• 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.

Open the Tweaks panel to adjust, live:

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

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.

• 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.