$\snippet{name: op_column, sign: '+', x: '140', y: '60', z: '200'}$
 
$\snippet{name: op_column, sign: '+', x: '290', y: '20', z: '310'}$
 
$\snippet{name: op_column, sign: '-', x: '300', y: '150', z: '150'}$
 
$\snippet{name: op_column, sign: '-', x: '180', y: '90', z: '90'}$
 
$\snippet{name: op_column, sign: '-', x: '520', y: '260', z: '260'}$
 
$\snippet{name: op_column, sign: '+', x: '740', y: '170', z: '910'}$
 
$\snippet{name: op_column, sign: '+', x: '230', y: '80', z: '310'}$
 
$\snippet{name: op_column, sign: '+', x: '60', y: '90', z: '150'}$