1st polygon is valid ...
2nd polygon is valid ...
MULTIPOLYGON(((2391 571,1863 571,1341 319,1863 361,2391 571)),((2391 571,2913 361,3441 319,2913 571,2391 571)))
((((2391, 571), (1863, 571), (1341, 319), (1863, 361))), (((2391, 571), (2913, 361), (3441, 319), (2913, 571))))
# of points: 8