If you want to write the same character for more times in a cell, you use REPT() function. You firstly write the character in " ", after you write the number of times it repeats.

 If you want to write the repetition of two different characters with different  arrangement, you use two nested REPT() function.

In third example, first REPT() function inside represent to write "#" character for 5 times; the second REPT() represents after 5 times # character 1 time "  " (double space) character. You can see it in result.