gistfile1.txt

public boolean transmuteBlock(int block1, int block2, World w, int x, int y, int z, int size) {
  // if the blockID is the same as block1
  if (w.getBlockId(x, y, z) == block1) {
    // then change it to block2
    w.setBlock(x, y, z, block2);
  // else if the blockID is the same as block2
  } else if (w.getBlockId(x, y, z) == block2) {
    // then change it to block1
    w.setBlock(x, y, z, block1);
  }
return false;
}