Hi Jan,

The problem is that all the rectangles have the same absolute coordinates {0, 0}, {2, 0.5} so a rotation about a point is not sufficient to position them in the right place. A translation is also needed. Or create rectangles with the right coordinates and rotations e.g.

positions = {{0, 0}, {2 Sqrt[3], 2}, {2*Sqrt[3], 7}};
rotations = {Pi/6, Pi/2, 0};
colors = {Black, Blue, Red};

rectangles = Rectangle[#, # + {2, 0.5}] & /@ positions;
rotatedRectangles = 
 MapThread[{#1, Rotate[#2, #3, #4]} &, {colors, rectangles, rotations, positions}];

Graphics[{Line[Append[positions, {7, 7}]], rotatedRectangles}]