The generator matrix

 1  0  1  1  1  1  1  1  1  0  1  1  1  0  1  1  X  1  1  1  1  1  1  1  X  1  1  1  1  1 aX  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  X  0  X aX  0  1 aX  1  X aX aX
 0  1  1  a (a+1)X+a+1  0 (a+1)X+1  a (a+1)X+a+1  1  0  a (a+1)X+1  1 (a+1)X+a+1 X+a  1  X (a+1)X+1 aX+a+1 X+a  X  1 aX+a+1  1  X aX+1 a+1  0 X+a  1 aX+1  a aX+a+1  X (a+1)X+a aX+a+1 aX (a+1)X+a+1 a+1  a a+1 a+1  X aX+a+1 (a+1)X+a aX X+a+1 aX+a (a+1)X+1 (a+1)X+a+1 (a+1)X+a (a+1)X+a (a+1)X+a aX+1 X+a aX+1 a+1 X+a  0 aX aX+1 (a+1)X+1  0  1  1  1  1  1 aX  1 aX  1  1  1
 0  0 (a+1)X  0  X  X (a+1)X  X (a+1)X  X  0  0  X  X  0 (a+1)X aX aX  0 (a+1)X aX (a+1)X aX aX (a+1)X  X  X  0 (a+1)X  X (a+1)X (a+1)X  X  0  X  0 (a+1)X  0 (a+1)X  X (a+1)X  X aX aX aX aX (a+1)X  0 (a+1)X  0  X  0 (a+1)X aX  0 aX aX aX  X  X  0 aX (a+1)X (a+1)X  X aX  X  0  0 aX aX aX (a+1)X (a+1)X  0
 0  0  0  X aX  X aX (a+1)X (a+1)X  0  X (a+1)X  0 aX aX (a+1)X  0  X  0 aX (a+1)X  X  0 aX  0  0 aX (a+1)X  0  X aX (a+1)X aX  X (a+1)X aX  X (a+1)X  0  0 aX  X  X (a+1)X  0 aX (a+1)X  0  X aX (a+1)X  0  0  X (a+1)X  0 aX (a+1)X  0 aX aX  X  X aX  X aX (a+1)X aX  X aX (a+1)X  0 (a+1)X  X (a+1)X

generates a code of length 75 over F4[X,sigma]/(X^2) who´s minimum homogenous weight is 217.

Homogenous weight enumerator: w(x)=1x^0+336x^217+450x^220+1488x^221+270x^224+264x^225+78x^228+384x^229+18x^232+96x^233+189x^236+432x^237+15x^240+72x^241+3x^252

The gray image is a linear code over GF(4) with n=300, k=6 and d=217.
This code was found by Heurico 1.16 in 1.79 seconds.