Plan a 30-day drawing challenge with progressive difficulty

You are an art instructor who designs month-long challenges that actually build skill. Build a 30-day drawing challenge with deliberate, rising difficulty — not 30 disconnected 'day X: draw a Y' prompts.

My context (I will fill in):
- Skill level: [BEGINNER / INTERMEDIATE / ADVANCED]
- Tool: [PENCIL / INK / DIGITAL / WATERCOLOR / MIXED MEDIA]
- Time per day: [15 MIN / 30 MIN / 1 HOUR]
- Theme or focus: [CHARACTERS / ANIMALS / ENVIRONMENTS / STILL LIFE / PORTRAITS / PERSPECTIVE / 'GENERAL FUNDAMENTALS']
- Any constraint I want throughout: [MONOCHROME ONLY / LIMITED PALETTE / INK ONLY, NO PENCIL UNDER-DRAW / 'NONE']

Design the 30 days in FOUR progressive phases of roughly equal length. For each phase, state its goal, then give the daily prompts. Each day needs:
1. DAY NUMBER + ONE-LINE PROMPT — a specific, concrete subject to draw (not 'draw an animal' — 'a sleeping cat curled so only its back and tail show').
2. THE FOCUS SKILL — the one fundamental that day trains (gesture, form, value, proportion, perspective, composition, texture).
3. THE CONSTRAINT — a single rule tuned to that day's skill (e.g. 'no outlines, build the cat only from shadow shapes').
4. ESTIMATED TIME — realistic for my stated daily budget.

Phase structure (rising difficulty):
- PHASE 1 (DAYS 1-7) — WARM-UP & OBSERVATION: simple subjects, short times, low pressure. Goal: build the daily habit and loosen up.
- PHASE 2 (DAYS 8-15) — FUNDAMENTALS DRILL: one named fundamental per day, slightly harder subjects.
- PHASE 3 (DAYS 16-23) — COMBINE SKILLS: pair two fundamentals (e.g. value + composition), introduce a timed element or harder reference.
- PHASE 4 (DAYS 24-30) — INTEGRATION: multi-element scenes or sustained studies that pull together everything from the prior phases. Include one make-up / catch-up day around day 25 and a final open piece on day 30.

Also include:
- A WEEKLY CHECK-IN at the end of days 7, 14, 21, and 28: one reflection question and one suggestion to adjust the next week based on how it is going.
- A MISSED-A-DAY RULE: how to handle a skipped day without quitting (never double up; just resume where you left off).
- A THIS-IS-WORKING-IF SIGNAL: 2-3 concrete signs of growth to watch for across the month.

Rules:
- Difficulty must rise across phases — no random ordering.
- Every subject must be drawable from life, photo reference, or imagination without special equipment.
- Keep each day's prompt finishable in the stated time.

Output the full 30-day plan grouped by phase.

Success signal: the output is good only if difficulty rises across four clear phases, every day names one focus skill with a real constraint, and there is a realistic missed-a-day rule so a skip does not end the challenge.