What is the final rectangle for r6c2=3?

Use the horizontal strip r6c1:r6c3, which is redrawn near the end of the walkthrough.

Where does the r7c2=4 clue go?

It occupies the 2x2 block r7c1:r8c2, not the tempting upper-left 2x2 preview.

The solved 8x7 board contains sixteen persistent rectangles covering all 56 cells.

MeowBlock! level guide

medium Target: 16 moves 16 colors

Solve MeowBlock! Level 31 by fixing the outer 5-cell bars, the central 2x2, and the lower-left redraw without accepting temporary previews.

Step 1: Anchor r3c7=5; commit top-left r1c7 and bottom-right r5c7 (5x1, area 5).
Step 2: Anchor r1c4=5; commit top-left r1c2 and bottom-right r1c6 (1x5, area 5).
Step 3: Anchor r5c4=5; commit top-left r5c2 and bottom-right r5c6 (1x5, area 5).
Step 4: Anchor r3c1=5; commit top-left r1c1 and bottom-right r5c1 (5x1, area 5).
Step 5: Anchor r2c4=3; commit top-left r2c3 and bottom-right r2c5 (1x3, area 3).
Step 6: Anchor r3c2=3; commit top-left r2c2 and bottom-right r4c2 (3x1, area 3).
Step 7: Anchor r4c3=4; commit top-left r3c3 and bottom-right r4c4 (2x2, area 4).
Step 8: Anchor r4c5=2; commit top-left r3c5 and bottom-right r4c5 (2x1, area 2).
Step 9: Anchor r3c6=3; commit top-left r2c6 and bottom-right r4c6 (3x1, area 3).
Step 10: Anchor r6c6=4; commit top-left r6c5 and bottom-right r7c6 (2x2, area 4).
Step 11: Anchor r6c7=2; commit top-left r6c7 and bottom-right r7c7 (2x1, area 2).
Step 12: Anchor r7c4=3; commit top-left r6c4 and bottom-right r8c4 (3x1, area 3).
Step 13: Anchor r8c6=3; commit top-left r8c5 and bottom-right r8c7 (1x3, area 3).
Step 14: On the final lower-left redraw, anchor r6c2=3; commit top-left r6c1 and bottom-right r6c3 (1x3, area 3).
Step 15: Anchor r7c2=4; commit top-left r7c1 and bottom-right r8c2 (2x2, area 4).
Step 16: Anchor r7c3=2; commit top-left r7c3 and bottom-right r8c3 (2x1, area 2).

Colors in this level:

Red, Violet, Blue, Green, Yellow, Cyan, Pink, Lavender, Purple, Mint, Orange, Lilac, Teal, Coral, Indigo, Gold

Do not release r7c3=2 as the horizontal r7c2:r7c3 preview; the persistent rectangle is r7c3:r8c3.
Do not make r7c2=4 into r6c1:r7c2, because that captures r6c2=3 and destroys the r6c1:r6c3 strip.
Do not merge the r6c7=2 pair with the r6c6=4 block; the verified bounds are r6c7:r7c7 and r6c5:r7c6.

Lock the r1c7:r5c7 and r1c1:r5c1 edge bars before filling the center.
Keep the r6c5:r7c6 2x2 block separate from the r6c7:r7c7 pair.
Leave the lower-left cluster open until its final 3, 4, 2, and 3 rectangles are visible together.

Board notes 5 details

Layout: Full 8-row by 7-column board with 56 playable cells. Clues: r1c4=5, r2c4=3, r3c1=5, r3c2=3, r3c6=3, r3c7=5, r4c3=4, r4c5=2, r5c4=5, r6c2=3, r6c6=4, r6c7=2, r7c2=4, r7c3=2, r7c4=3, r8c6=3.
Goal: Partition all 56 cells into sixteen rectangles: the final bounds are r1c1:r5c1, r1c2:r1c6, r1c7:r5c7, r2c2:r4c2, r2c3:r2c5, r2c6:r4c6, r3c3:r4c4, r3c5:r4c5, r5c2:r5c6, r6c1:r6c3, r6c4:r8c4, r6c5:r7c6, r6c7:r7c7, r7c1:r8c2, r7c3:r8c3, and r8c5:r8c7.
Opening: The source first commits r3c7=5 as r1c7:r5c7, r1c4=5 as r1c2:r1c6, r5c4=5 as r5c2:r5c6, and r3c1=5 as r1c1:r5c1, then closes the small upper regions before the lower redraw.
Danger Zone: Do not keep the horizontal r7c2:r7c3 preview for r7c3=2, and do not spread r6c7=2 across row 6. The final lower regions must preserve r6c4:r8c4, r7c1:r8c2, and r7c3:r8c3.
Mechanics: All sixteen clues are integer areas summing to 56. The walkthrough redraws lower previews, so only rectangles that persist through the solved frame are authoritative.

What is the final rectangle for r6c2=3?
Use the horizontal strip r6c1:r6c3, which is redrawn near the end of the walkthrough.
Where does the r7c2=4 clue go?
It occupies the 2x2 block r7c1:r8c2, not the tempting upper-left 2x2 preview.
How many rectangles solve Level 31?
The solved 8x7 board contains sixteen persistent rectangles covering all 56 cells.