File under “Dotting your T s and crossing your eyes”: The cliche “Make sure to dot your f’s and cross your T s” doesn’t go nearly far enough.
Make sure you dot your J’s, too.
And cross your D’s. Wait. You don’t have to do that anymore.
A crossed D was an Old English character called eth—O— which indicated the “th” sound, as did sister character thorn (see page 184). But like thorn, eth is obsolete. Though it’s redundant to say in its visually punnish way, it has seen its Oeth.'