The generator matrix

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

generates a code of length 30 over Z4[X]/(X^2+2) who´s minimum homogenous weight is 23.

Homogenous weight enumerator: w(x)=1x^0+90x^23+694x^24+2804x^25+6958x^26+16048x^27+30240x^28+47622x^29+52953x^30+47450x^31+30937x^32+16548x^33+6471x^34+2316x^35+716x^36+222x^37+47x^38+16x^39+4x^40+4x^41+3x^42

The gray image is a code over GF(2) with n=240, k=18 and d=92.
This code was found by Heurico 1.16 in 190 seconds.