Stereoisomerism in 1,2-cyclobutanediol

Question

For 1,2-cyclobutanediol, it's given in my book that it has 3 stereo isomers. Here's the passage:

My questions:

1. How can it have stereo-isomers?
2. What will the meso compounds look like?

Answer 1

These two isomers are enantiomers, i.e. mirror images, of each other:

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This one has a plane of symmetry through the molecule and is therefore meso:

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