Thanks to Deepa Vaishnavi, who posted it on her FB page:

The Spelling Chequer (or poet tree without misttakes)

Eye have a spelling chequer
It came with my pea sea
It plainly marks four my revue
Miss steaks eye cannot see

Each thyme when I have struct the quays
Eye weight four it two say
If watt eye rote is wrong or rite
It shows me strait a weigh

As soon as a mist ache is maid
It nose bee fore too late
And eye can put the error rite
Eye really fined it grate

I’ve run this poem threw it
I’m sure your policed to no
It’s letter perfect in its weigh
My chequer tolled me sew

       -Author Unknown