Binary (28,21)-code with minimal distance 4

[1000000000000000000001110101]
[0100000000000000000001101011]
[0010000000000000000001110000]
[0001000000000000000001101000]
[0000100000000000000001100100]
[0000010000000000000001100010]
[0000001000000000000001100001]
[0000000100000000000001010100]
[0000000010000000000001001010]
[0000000001000000000001010001]
[0000000000100000000001001001]
[0000000000010000000001000101]
[0000000000001000000001000011]
[0000000000000100000000110100]
[0000000000000010000000101010]
[0000000000000001000000110001]
[0000000000000000100000101001]
[0000000000000000010000100101]
[0000000000000000001000100011]
[0000000000000000000100010101]
[0000000000000000000010001011]