The important components:
column-count: 5; column-gap: 15px; column-fill: auto;
And the repetitive boxes(rectangles) inside it, will contain:
display: inline-block; column-break-inside: avoid;
See the Pen Using Float to Place Article Elements Side-by-Side by Harshal Carpenter (@McQuinTrix) on CodePen.
It is still not fully supported by any browser, you will have to use
-webkit- with Chrome & Safari and
-moz- with Mozilla. Internet Explorer 10 and Opera 11.1 supports it.
There is one fallback to it: every inner box loads at the same time and it could prove to be a big burden for a page to load in first go. You will have to make it more responsive using
@media queries. For example, this pen I designed for FreeCodeCamp’s camper news is optimized for mobile browser too.
Find more information on CSS-Tricks.