{
  {type='rows', default={font={size=21}, line_height=35},
    {type='text', font={size=28}, line_height=50,
      {'Lua@{Lua} > expressions',
        attrs={
          Lua={target='--lua'},
        }},
    },
    {type='filler', height=15},
    {type='text',
        {'Anywhere in a statement you might use (not define) a variable, you can use an em@{expression} in its place. Some examples:',
          attrs={
            em={font={italic=true}}}}},
    {type='text', '5', font={size=24}},
    {type='text', '    All values (numbers, strings, tables, etc.) are types.'},
    {type='filler', height=10},
    {type='text', '5+3', font={size=24}},
    {type='text', '    You can add (+), subtract (-), multiply (*), divide (/), compute the remainder (%) of two numbers.'},
    {type='filler', height=10},
    {type='text', '4+3*2', font={size=24}},
    {type='text', '    Expressions can contain other expressions, and they follow the precedence rules you learned in school.'},
    {type='text', '    Multiplication, division and remainder happen before addition and subtraction.'},
    {type='filler', height=10},
    {type='text', '(4+3) * 2'},
    {type='text', '    To ensure one expression is calculated before another, use parentheses ()'},
    {type='filler', height=10},
    {type='text', 'x == y'},
    {type='text', "    You can compare two expressions to determine if they're equal (==), not equal (~=), greater (>), lesser (<), greater or equal (>=), lesser or equal (<=)."},
    {type='text', "    These expressions are handy in the conditions of 'if' statements and loops."},
    {type='filler', height=10},
    {type='text', 'x == 3 and y > 4', font={size=24}},
    {type='text',
        {'    Comparisons return em@{booleans} true or false, which can be combined using and/or.',
         attrs={
          em={font={italic=true}}}}},
    {type='filler', height=10},
    {type='text', 'not x == 3', font={size=24}},
    {type='text', '    Turn a boolean into its opposite.'},
    {type='filler', height=10},
    {type='text', 'nil or 3', font={size=24}},
    {type='text', '    All non-boolean values act like true in and/or except for nil.'},
    {type='filler', height=10},
    {type='text', '"hello ".."world"', font={size=24}},
    {type='text', '    String values can be combined using ..'},
    {type='filler', height=10},
    {type='text', 'add(2, 3)', font={size=24}},
    {type='text', '    Function calls can act as expressions as well as statements.'},
  }
}