Code:
sample,var,value
s1,v1,aa
s1,v2,tt
s1,v3,aa
s1,v4,gg
s2,v1,tt
s2,v2,aa
s2,v3,aa
s2,v4,gg
s3,v1,at
s3,v3,aa
s3,v4,tt
s4,v1,tt
s4,v2,at
s4,v3,aa
s4,v4,gt
s5,v1,aa
s5,v2,tt
s5,v3,aa
s5,v4,gt
s6,v1,aa
s6,v2,aa
s6,v3,aa
s6,v4,tt
s7,v1,aa
s7,v2,aa
s7,v3,at
s7,v4,ag
s8,v1,aa
s8,v2,tt
s8,v3,at
s8,v4,ag
s9,v1,aa
s9,v2,at
s9,v3,tt
s9,v4,gg
s10,v1,aa
s10,v2,at
s10,v3,aa
s10,v4,ag
s11,v1,aa
s11,v2,aa
s11,v3,tt
s11,v4,gg
s12,v1,tt
s12,v2,tt
s12,v3,tt
s12,v4,ag
s13,v1,aa
s13,v2,at
s13,v3,aa
s13,v4,ag
s14,v1,at
s14,v2,aa
s14,v3,at
s14,v4,aa
s15,v1,aa
s15,v2,aa
s15,v3,tt
s15,v4,aa