Monte Carlo mass–radius constraints for 4U 1746−37 over a sampled grid of fixed blocking factors, ℬ = 0, 0.1, 0.2, …, 0.8. Each panel shows the distribution of accepted solutions in the M–R plane for the indicated value of ℬ. As the assumed blocking factor increases, the allowed region shifts systematically from the unusually compact, low-mass regime toward higher masses and larger radii. The white solid and dot-dashed contours enclose 68% and 95% of the accepted realizations, respectively. The gray diagonal line marks the causality limit, β ≡ GM/(Rc²) = 1/2.94. Overlaid are representative equations of state for nucleonic matter (KIDS, SGI, PAL6, APR3, ENG, H3) and strange-quark matter (SQM1, SQM2, SQM3).