Make your window an inch or two bigger than than the width of one float. All floats should be the same size. This document should be pixel-perfect identical to this one and this one at all window sizes. Try resizing the window so that floats wrap in one or two columns.

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this is a float this is a float this is a float this is a float this is a float this is a float this is a float
this is a float this is a float this is a float this is a float this is a float this is a float this is a float
this is a float this is a float this is a float this is a float this is a float this is a float this is a float