How to remove the space between the blocks without Masonry?

Good time of day. How to remove the gap between b1 and b3(in red)? Negative margins, positioning is not an option maybe the amount of content in b2 is not fixed.
March 23rd 20 at 18:42
1 answer
March 23rd 20 at 18:44
.b2 {
 width: calc(50% - 2px); // 2px can be removed when you remove the border from b3
 float: right;

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