},
          {
            title: 'Limits on a custom operator',
            pic: 'limits-4.gif',
            latex: `\\operatorname{custom-operator}^{above}_{below}\\mathop{operator}^{above}_{below}`,
          },
        ],
        'Environments (<kbd>begin...end</kbd>)': [
          {
            title: 'Matrix (pmatrix)',
            latex: `A_{m,n} =
            \\begin{pmatrix}
                a_{1,1} & a_{1,2} & \\cdots & a_{1,n} \\\\
                a_{2,1} & a_{2,2} & \\cdots & a_{2,n} \\\\
       