The generator matrix

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

generates a code of length 63 over F4[X,sigma]/(X^2) who´s minimum homogenous weight is 172.

Homogenous weight enumerator: w(x)=1x^0+258x^172+276x^173+516x^175+2139x^176+780x^177+1128x^179+4518x^180+1440x^181+1788x^183+6531x^184+2232x^185+2568x^187+8697x^188+2568x^189+2568x^191+8490x^192+2460x^193+2280x^195+7059x^196+1728x^197+1164x^199+2676x^200+576x^201+264x^203+465x^204+228x^205+12x^207+54x^208+15x^212+30x^216+12x^220+12x^224+3x^232

The gray image is a linear code over GF(4) with n=252, k=8 and d=172.
This code was found by Heurico 1.16 in 18 seconds.