ClearAll[rectilinearPoly]
 rectilinearPoly = Polygon@(Join @@ (Partition[#, 2, 1, 1] /.
 {{a_Real, b_}, {c_, d_}} :> {{a, b}, {c, b}, {c, d}})) &;
 

***Examples:***

 SeedRandom[1]
 coords = RandomReal[{-1, 1}, {5, 6, 2}];

 Row[Graphics[{EdgeForm[Gray], FaceForm[Opacity[.5, RandomColor[]]], 
 rectilinearPoly@#, Red, PointSize[Medium], Point@#}, ImageSize -> 1 -> 100]& /@
 (#[[FindShortestTour[#][[2]]]] & /@ coords), Spacer[5]]

[![enter image description here][1]][1]

 Row[Graphics[{EdgeForm[Gray], FaceForm[Opacity[.5, RandomColor[]]], 
 rectPoly@#, Red, PointSize[Medium], Point@#}, ImageSize -> 1 -> 100] & /@ 
 coords, Spacer[5]]

[![enter image description here][2]][2]


 [1]: https://i.sstatic.net/JrVr2.png
 [2]: https://i.sstatic.net/CUWgd.png