A rock flows under a stress of about 2.2 × 10⁸ Pa, and its density is 2900 kg/m³…

Step 1. Earth. $\dfrac{2.2 \times 10^{8}\ \text{Pa}}{2900\ \text{kg/m}^3 \times 9.8\ \text{m/s}^2} = 7.74 \times 10^{3}\ \text{m}$.

Step 2. Mars. $\dfrac{2.2 \times 10^{8}\ \text{Pa}}{2900\ \text{kg/m}^3 \times 3.7\ \text{m/s}^2} = 2.05 \times 10^{4}\ \text{m}$.

Step 3. Moon. $\dfrac{2.2 \times 10^{8}\ \text{Pa}}{2900\ \text{kg/m}^3 \times 1.6\ \text{m/s}^2} = 4.74 \times 10^{4}\ \text{m}$.