text: var a = [];
  for (let j = 0; j < 6; ++j) {
    e = 3; 
    for each (let c in [10, 20, 30]) { 
      a.push(e);
      e = c; 
    }
  }
  for (let j = 0; j < 6; ++j) {
    assertEq(a[j*3 + 0], 3);
    assertEq(a[j*3 + 1], 10);
    assertEq(a[j*3 + 2], 20);
  }
  