void tick(Field *f)
{
    Field *matrix = createField(f->xsize, f->ysize);
    matrix=f;
    int j,i;
    int a=f->xsize-1;
    int b=f->ysize-1;
    int k;
    for (j=0; j<=b; j++){
        for (i=0; i<=a; i++){
            k=0;
            if ((i-1)>=0 && (j-1)>=0 && matrix->cells[j-1][i-1]==ALIVE) //vasen ylä
                k++;
            if ((i-1)>=0 && (j+1)<=b && matrix->cells[j+1][i-1]==ALIVE) //vasen ala
                k++;
            if ((i+1)<=a && (j-1)>=0 && matrix->cells[j-1][i+1]==ALIVE) //oikea ylä
                k++;
            if ((i+1)<=a && (j+1<=b) && matrix->cells[j+1][i+1]==ALIVE) //oikea ala
                k++;
            if (i-1>=0 && matrix->cells[j][i-1]==ALIVE) //vasen
                k++;
            if (j-1>=0 && matrix->cells[j-1][i]==ALIVE) //ylä
                k++;
            if (i+1<=a && matrix->cells[j][i+1]==ALIVE) //oikea
                k++;
            if (j+1<=b && matrix->cells[j+1][i]==ALIVE) //ala
                k++;

            if (matrix->cells[j][i]==ALIVE){
                if (k<2)
                    f->cells[j][i]=DEAD;
                if (k==2 || k==3)
                    f->cells[j][i]=ALIVE;
                if (k>3)
                    f->cells[j][i]=DEAD;
            }
            if (matrix->cells[j][i]==DEAD)
                if (k==3)
                    f->cells[j][i]=ALIVE;

        }
    }
    releaseField(matrix);
}