The title of my last post is the cause of this.
First person singular: lie / lay
First person plural: lie / lay
Second person singular: lie / lay
Second person plural: lie / lay
Third person singular: lies / lays
Third person plural: lie / lay
All: lay / laid
All: lying / laying
I lie on the bed (I recline)
He lies on the bed (He reclines)
They lie on the bed (They recline)
I was lying on the bed. (I was reclining)
I lay on the bed. (I reclined)
I lay down my book.
He lays down his book.
They lay down their books.
I was laying down my books.
I laid down my books.
National Socialism Lay in a Fiery Ditch
Further complicating the matter, I suppose, is the American usage of "lay" meaning "to have sex with" and "lay (out)" meaning "to knock over," not to mention "lie" meaning "to tell an untruth" and "lay" meaning "to produce an egg (or flatulence)."
He lay on the bed.
He laid him out in the middle of the restaurant.
He laid him on the beach.
He lied to everyone.
I need to get laid.
He laid one.
I need to lie down.