Typical 12 column grid based on CSS Grid Layout

four columns
four columns
four columns
eight columns
four columns
three columns
three columns
three columns
three columns
six columns
six columns
twelve collumns

Not a typical 12 column grid based on CSS Grid Layout

four columns two rows
four columns three rows
four columns
four columns
three columns
one
one
three columns
six columns
three columns
three columns
twelve collumns