/* GoldYeld — interactive Position Simulator. Two axes: allocation amount (slider) + entry date (draggable marker on the chart). Entry price follows a synthetic-but-realistic gold price history; from entry→today we compound yield every 36 days (in gold); right of today is a dashed "future unknown" zone. Exports window.PositionSimulator. Reads window.GC for colors/fonts. */ const SPOT = 2016; // gold price "today" const HIST_DAYS = 365; // 12 months of history, day 0 = 12mo ago, 365 = today const PROJ_DAYS = 108; // ~3 cycles of future projection const TOTAL_DAYS = HIST_DAYS + PROJ_DAYS; const CYCLE_LEN = 36; // days per yield cycle const APR = 0.20; const CYCLE_RATE = APR * CYCLE_LEN / 365; // simple (non-compounding) yield per cycle, in gold const TODAY = new Date(2026, 5, 2); // Jun 2, 2026 // monthly anchor prices, oldest → today (13 values @ day 0,30,…,360, last≈365) const ANCHORS = [1812, 1798, 1845, 1888, 1864, 1902, 1955, 1928, 1972, 1949, 2004, 1988, SPOT]; function priceAt(day) { if (day >= HIST_DAYS) return SPOT; if (day <= 0) day = 0; const seg = day / 30, i = Math.floor(seg), f = seg - i; const a = ANCHORS[i], b = ANCHORS[Math.min(i + 1, ANCHORS.length - 1)]; let p = a + (b - a) * f; p += 6 * Math.sin(day * 0.13) + 3.5 * Math.sin(day * 0.41 + 1.2); // texture return p; } function dateForDay(day) { const d = new Date(TODAY); d.setDate(d.getDate() - (HIST_DAYS - day)); return d; } function fmtDate(d) { return d.toLocaleDateString('en-US', { month: 'short', day: 'numeric', year: 'numeric' }); } function fmtUSD(n) { return '$' + Math.round(n).toLocaleString('en-US'); } function PositionSimulator({ c }) { const F = (window.GC && window.GC.fonts) || { d: 'Georgia,serif', b: 'system-ui,sans-serif', m: 'monospace' }; const [amount, setAmount] = React.useState(1000000); const [entry, setEntry] = React.useState(0); // 12 months ago const [hoverDay, setHoverDay] = React.useState(null); const svgRef = React.useRef(null); // ---- derived figures ---- const entryPrice = priceAt(entry); const oz0 = amount / entryPrice; const daysHeld = Math.max(0, HIST_DAYS - entry); const cycles = Math.floor(daysHeld / CYCLE_LEN); const ozNow = oz0 * (1 + CYCLE_RATE * cycles); // simple yield, not compounded const value = ozNow * SPOT; const yieldUSD = (ozNow - oz0) * SPOT; const totalRet = (value - amount) / amount; const isToday = entry >= HIST_DAYS - 1; // combined APR = yield APR + simple annualized gold-price move over the holding period (no compounding) const goldAPR = (!isToday && daysHeld >= 14) ? ((SPOT / entryPrice - 1) * (365 / daysHeld)) : 0; const combinedAPR = APR + goldAPR; const [tip, setTip] = React.useState(false); // ---- chart geometry (dynamic window: entry → today → short projection) ---- const W = 660, H = 226, PROJ = 72; const xMin = entry, xMax = HIST_DAYS + PROJ; const xFor = (day) => ((day - xMin) / (xMax - xMin)) * W; const valsAt = (day) => { const price = day <= HIST_DAYS ? priceAt(day) : SPOT; const cyc = Math.max(0, Math.floor((day - entry) / CYCLE_LEN)); const oz = oz0 * (1 + CYCLE_RATE * cyc); // simple yield, not compounded return { wy: oz * price, go: oz0 * price }; }; // sample realized (entry→today) and projection (today→end) const step = 3; const realized = [], proj = []; for (let d = entry; d <= HIST_DAYS; d += step) realized.push([d, valsAt(d)]); if (realized.length === 0 || realized[realized.length - 1][0] !== HIST_DAYS) realized.push([HIST_DAYS, valsAt(HIST_DAYS)]); for (let d = HIST_DAYS; d <= xMax; d += step) proj.push([d, valsAt(d)]); const allY = [amount, ...realized.map(p => p[1].wy), ...proj.map(p => p[1].wy), ...realized.map(p => p[1].go)]; const yMax = Math.max(...allY) * 1.04, yMin = Math.min(...allY) * 0.97; const yFor = (v) => H - ((v - yMin) / (yMax - yMin)) * H; const poly = (pts, key) => pts.map(([d, v]) => `${xFor(d)},${yFor(v[key])}`).join(' '); const areaPts = `${xFor(entry)},${H} ${poly(realized, 'wy')} ${xFor(HIST_DAYS)},${H}`; const monthsAgo = Math.round(daysHeld / 30); const entryLabel = isToday ? 'Today' : (monthsAgo <= 1 ? '~1 month ago' : `~${monthsAgo} months ago`); const presets = [['Today', HIST_DAYS], ['1M', HIST_DAYS - 30], ['3M', HIST_DAYS - 90], ['6M', HIST_DAYS - 182], ['12M ago', 0]]; const amtChips = [100000, 250000, 500000, 1000000]; const kpis = [ ['Entry price', `$${entryPrice.toFixed(0)} / oz`, false, fmtDate(dateForDay(entry))], ['Gold held', `${ozNow.toFixed(2)} oz`, false, `${(ozNow * 31.1035 / 1000).toFixed(2)} kg`], ['Cycles paid', isToday ? '—' : String(cycles), false, isToday ? 'not started' : `every ${CYCLE_LEN} days`], ['Yield earned', isToday ? '$0' : `+${fmtUSD(yieldUSD)}`, true, isToday ? 'accrues over time' : `${(APR * 100).toFixed(1)}% APR`], ]; return (
{/* header */}
EXAMPLE · SIMULATION Adjust the amount and your entry date
setTip(true)} onMouseLeave={() => setTip(false)}>
= 0 ? c.up : '#b4543a', borderRadius: 12, padding: '8px 16px', boxShadow: combinedAPR >= 0 ? '0 6px 16px rgba(74,125,87,0.28)' : '0 6px 16px rgba(180,84,58,0.28)', cursor: 'help' }}> COMBINED APR i {combinedAPR >= 0 ? '+' : ''}{(combinedAPR * 100).toFixed(1)}%
{tip && (
How Combined APR is built

Two stacked engines on the same gold, annualized over your holding period:

{[ ['Yield', `+${(APR * 100).toFixed(1)}%`, 'Paid in gold every 36 days · simple, not compounded', c.gold], ['Gold price', isToday ? '—' : `${goldAPR >= 0 ? '+' : ''}${(goldAPR * 100).toFixed(1)}%`, isToday ? 'No holding period yet' : `$${entryPrice.toFixed(0)} → $${SPOT.toLocaleString('en-US')}, annualized`, c.faint], ].map(([l, v, sub, dot]) => (
{l} {v}
{sub}
))}
Combined APR {combinedAPR >= 0 ? '+' : ''}{(combinedAPR * 100).toFixed(1)}%

Illustrative. Gold-price component reflects past movement; future prices are unknown. Yield is GoldYeld’s {(APR * 100).toFixed(0)}% target APR, paid in gold and not compounded.

)}
{/* controls */}
I allocate {fmtUSD(amount)}
setAmount(+e.target.value)} style={{ width: '100%', marginTop: 12, background: `linear-gradient(90deg, ${c.gold} ${(amount - 10000) / (2000000 - 10000) * 100}%, ${c.line} ${(amount - 10000) / (2000000 - 10000) * 100}%)` }} />
{amtChips.map(a => ( setAmount(a)} style={{ fontFamily: F.m, fontSize: 11, padding: '5px 11px', borderRadius: 999, cursor: 'pointer', border: `1px solid ${amount === a ? c.gold : c.line}`, color: amount === a ? c.gold : c.sub, background: amount === a ? c.goldWash || '#f6efdf' : 'transparent' }}>{a >= 1000000 ? `$${a / 1000000}M` : `$${a / 1000}k`} ))}
I entered {entryLabel}
setEntry(+e.target.value)} style={{ width: '100%', marginTop: 12, background: `linear-gradient(90deg, ${c.line} ${entry / HIST_DAYS * 100}%, ${c.gold} ${entry / HIST_DAYS * 100}%)` }} />
{presets.map(([lab, d]) => { const on = Math.abs(entry - d) < 3; return setEntry(d)} style={{ fontFamily: F.m, fontSize: 11, padding: '5px 11px', borderRadius: 999, cursor: 'pointer', border: `1px solid ${on ? c.gold : c.line}`, color: on ? c.gold : c.sub, background: on ? c.goldWash || '#f6efdf' : 'transparent' }}>{lab}; })}
{/* value + chart */}
{isToday ? 'Starting value' : 'Value today'}
{fmtUSD(value)}
{fmtUSD(amount)} allocated{isToday ? '' : ` · +${fmtUSD(value - amount)}`}
{kpis.map(([l, v, g, sub]) => (
{l}
{v}
{sub &&
{sub}
}
))}
POSITION VALUE OVER TIME with yield price only
{ const r = svgRef.current.getBoundingClientRect(); const frac = (e.clientX - r.left) / r.width; setHoverDay(Math.max(entry, Math.min(xMax, Math.round(xMin + frac * (xMax - xMin))))); }} onPointerLeave={() => setHoverDay(null)} style={{ width: '100%', height: 226, display: 'block', overflow: 'visible', cursor: 'crosshair' }}> {/* future zone shading */} {/* area under realized */} {/* price-only baseline */} {/* realized with-yield */} {/* projection dashed */} {/* today divider */} TODAY FUTURE · price unknown {/* hover crosshair */} {hoverDay != null && (() => { const hv = valsAt(hoverDay); return ( HIST_DAYS ? c.goldSoft : c.gold} stroke="#fff" strokeWidth="2" /> ); })()} {/* entry marker */} ENTRY {hoverDay != null && (() => { const hv = valsAt(hoverDay); const cyc = Math.max(0, Math.floor((hoverDay - entry) / CYCLE_LEN)); const isFut = hoverDay > HIST_DAYS; const frac = (hoverDay - xMin) / (xMax - xMin); const yieldNow = hv.wy - hv.go; return (
{fmtDate(dateForDay(hoverDay))} {isFut ? 'PROJECTED' : 'REALIZED'}
{fmtUSD(hv.wy)}
{[ ['Gold price', isFut ? `$${SPOT.toLocaleString('en-US')} (assumed)` : `$${(hoverDay <= HIST_DAYS ? priceAt(hoverDay) : SPOT).toFixed(0)} / oz`], ['Yield to date', `+${fmtUSD(yieldNow)}`], ['Cycles paid', `${cyc} · batch ${String(24 - Math.floor((HIST_DAYS - hoverDay) / CYCLE_LEN)).padStart(3, '0')}`], ].map(([l, v]) => (
{l}{v}
))}
); })()}
ENTRY {fmtDate(dateForDay(entry))} @ ${entryPrice.toFixed(0)} SPOT TODAY ${SPOT.toLocaleString('en-US')}
{/* footnote */}
{isToday ? 'Enter today and nothing is realized yet — tomorrow’s gold price is unknown, but yield still accrues in gold every 36 days (dashed). Drag the marker into the past to see a real entry play out.' : `Entered ${entryLabel.toLowerCase()} at $${entryPrice.toFixed(0)}/oz: gold moved to $${SPOT.toLocaleString('en-US')} and ${cycles} yield ${cycles === 1 ? 'cycle has' : 'cycles have'} paid in gold. Illustrative — based on GoldYeld’s ${(APR * 100).toFixed(1)}% target APR (simple, not compounded), not a guarantee.`}
); } Object.assign(window, { PositionSimulator });