int narray[][] = new int[6][4];

void setup()
{
size(700,700);
int number = 0;

//формирование одинаковых пар чисел
for (int i = 0;i < 6; i++)
{
number++;
for (int j = 0;j < 4; j++)
{
if (i%2 == 0 && j%2 == 0)
{
narray[i][j] = number;
}

if (i%2+1!= 0 && j%2+1 != 0)
{
narray[i][j] = number;
}

}

}

}

void draw(){

}

void mouseClicked() {
  
for (int i = 0;i < 6; i++)
{
for (int j = 0;j < 4; j++)
{
int index1 = (int)random(0,6);
int index2 = (int)random(0,4);
//обмен значений
int number = narray[i][j];
narray[i][j] = narray[index1][index2];
narray[index1][index2] = number;
}

}

for (int i = 0;i < 6; i++)
{
for (int j = 0;j < 4; j++)
{
textSize(25);
text(narray[i][j],i*50 + 20,j*50+20);
}
}

}