# RegionPlot looks wrong

I have the following simple RegionPlot of a RegionUnion:

RegionPlot[RegionUnion[
Rectangle[{-0.125, -0.125}, {0.125, 0.125}],
Rectangle[{0.126, -0.05}, {0.425, 0.05}]
], AspectRatio -> Automatic]


This looks all good, but when I change the 0.126 to 0.125 to merge the two rectangles the union drops two corners of the region:

What is going wrong here and how can I display the correct region? Strangely enough with different numeric values it seems to work.

• What version of Mathematica are you running? I got my results with V10.2 running on OS X 10.10.2 Sep 19 '15 at 23:38
• I get what the OP has shown with V10.0 in Windows 10 (64-bit) Sep 20 '15 at 7:20
• Strange, I get what m_goldberg has on versions 10.0.2, 10.1 and 10.2 (Win 8.1 64 bit). Sep 20 '15 at 14:57
• @Hubble07 What is your $ReleaseNumber? Sep 20 '15 at 15:03 • $ReleaseNumber is 0 Sep 20 '15 at 15:46

## 1 Answer

This is not an answer, but a comment in which I need to show an image.

I don't see any problem with your code. When I evaluate

RegionPlot[
RegionUnion[
Rectangle[{-0.125, -0.125}, {0.125, 0.125}],
Rectangle[{0.125, -0.05}, {0.425, 0.05}]],
AspectRatio -> Automatic]


I get

which is exactly what I expect. Are you getting something different? Or, if you getting the same image, why do you think it is wrong?

• Added an image showing how it looks for me Sep 19 '15 at 23:36
• I'm on 10.2 and duplicated m_goldberg's result. Sep 20 '15 at 1:58
• I get (almost) your result. That "(almost)" is because the OP has 0.126 in the second rectangle instead of the 0.125 you used. Sep 20 '15 at 15:01
• @SjoerdC.deVries: The image I show is when using 0.125. With 0.126 it looks ok, but the rectangles are not joined (which is not what I want). Sep 21 '15 at 16:49