What editor supports 7 equal-width columns, as mentioned/shown? I.e. show a single file in many columns? And how does it look when you press page-down or scro

What editor supports 7 equal-width columns, as mentioned/shown? I.e. show a single file in many columns? And how does it look when you press page-down or scroll? Or insert a line on the left? Any lag? Or is the only solution to clone the file into 7 different views? Seems hard to keep track of. Edit: ok, I guess Figure 3 is 7 separate files? But without tabs at the top?