A usenet poster to news:comp.lang.tcl asked how to display text with super and subscripts. Kevin Kenny was kind enough to demonstrate two ways to do this:
font create normal -family times -size 12
font create small -family times -size 10
grid [text .t -width 40 -height 5 -font normal] -columnspan 2
.t tag configure subscript -font small -offset -5p
.t insert 1.0 "Little Willy took a drink,\n" {}
.t insert 2.0 " But he will drink no more,\n" {}
.t insert 3.0 "For what he thought was H" {} "2" subscript "O\n" {}
.t insert 4.0 " Was H" {} "2" subscript "SO" {} "4" subscript "!" {}
button .b1 -text "H\u2082O" -command { exit 0 }
button .b2 -text "H\u2082SO\u2084" -command { exit 1 }
grid .b1 .b2 -pady 5
grid columnconfigure . { 0 1 } -weight 1