BANK GROWTH: $100 / MONTH FOR 30 YEARS

bank-growth.html: Self-contained, offline interactive animation. Open in a full
browser and select Play 30 years. Includes pause, timeline scrubbing, and final totals.
No installation, Python, or internet connection is required.

bank-growth.mp4: Video animation with a final hold on the results; suitable for
PowerPoint, video players, and iPad. No audio.

SOURCE CODE
source/animation.html: Editable HTML/CSS/JavaScript visualization source.
bank-growth.html also includes its full source and standalone display styles.
source/calculate.py: Pure Python verification and CSV generation; no NumPy required.
Run: python3 source/calculate.py
monthly-balances.csv: Values for months 0 through 360.

ASSUMPTIONS
Initial balance $0. Deposit $100 at the BEGINNING of each month, then credit
interest at 0.04 / 12 per month. No fees, taxes, withdrawals, or rate changes.
All computations retain full precision; only displayed values are rounded.
Animation interpolates between monthly observations for smooth movement.

RECURRENCE
B_0 = 0
B_n = (B_(n-1) + 100) * (1 + 0.04/12)
Linear comparison: D_n = 100 * n
Closed form: B_n = 100 * (1+r) * ((1+r)^n - 1) / r, where r=0.04/12.

FINAL TOTALS
Total deposited: $36,000
Total at the end: $69,636.29
Interest earned: $33,636.29
