The generator matrix

 1  0  0  1  1  1  X  1  1  1  1  X  X X+2  2
 0  1  0  0  3 X+3  1 X+2  X  3  1  2  1  1  2
 0  0  1  1  1  0  1  3 X+2 X+2 X+1  1  X  3  X
 0  0  0  X X+2 X+2  2  X  0  X X+2 X+2  X  X  X

generates a code of length 15 over Z4[X]/(X^2+2,2X) who´s minimum homogenous weight is 12.

Homogenous weight enumerator: w(x)=1x^0+350x^12+656x^14+751x^16+240x^18+50x^20

The gray image is a code over GF(2) with n=60, k=11 and d=24.
This code was found by Heurico 1.16 in 7.63 seconds.