What does the 3×4 specification of brush font mean?

Calligraphy is limited to "the standard size is more than four feet", which means that it is ok to be larger than four feet.

Common specifications and dimensions of calligraphy:

Tripod: 50* 100 Big Tripod: 69* 100 Tripod fully open: 100x55 Tripod single: 100x27 Tripod horizontal batch: 100x55 Tripod joint:/kloc-0.

Four-legged fully open: 138x69 Four-legged single:138x64 Four-legged horizontal batch: 138x69 Four-legged football association:138x64 Four-legged bucket: 69x68 Four-legged three-open: 69x46 Four-legged four-open: 46x34 Four-legged six-open:

Five-foot fully open: 153x84 five-foot single: 153x42 five-foot horizontal batch: 153x84 five-foot joint: 153x42 five-foot bucket: 84x77

Six feet fully open: 180x97 six feet three open: 97x60 six feet joint: 180x49 six feet square: 97x90

Seven feet fully open: 238x 129

In the early days of the People's Republic of China, one foot in calligraphy and painting was equal to 30 cm. Now it's all 1 foot equals 33 centimeters.