$\snippet{name: op_column, sign: '-', x: '90', y: '36', z: '54'}$
 
$\snippet{name: op_column, sign: '+', x: '56', y: '28', z: '84'}$
 
$\snippet{name: op_column, sign: '+', x: '83', y: '15', z: '98'}$
 
$\snippet{name: op_column, sign: '-', x: '49', y: '18', z: '31'}$