Green’s Dictionary of Slang

1. bad handwriting.

c.1698		B.E. Dict. Canting Crew n.p.: Pot-hooks Scrawls or bad Writing.
[1711		Swift letter xxix 8 Sept. in Journal to Stella (1901) 289: No, ’tis not your pen is bewitched, Madam Stella, but your scrawling, splay-foot pot-hooks] .
1796		Grose Classical Dict. of the Vulgar Tongue (3rd edn) n.p.: Pothooks and Hangers. A scrawl, bad writing.
1816		J.H. Lewis Lectures on Art of Writing (1840) 42: I devote the next Quarter to what is vulgarly designated ‘pot-hooks and hangers’.
1821		Egan Life in London (1869) 312: Who’s to understand it? vy it’s full of pothooks and hangers.
1848		Flash Dict. in Sinks of London Laid Open.
1861		Worcs. Chron. 2 Oct. 4/5: The so-called hieroglyphics were nothing more than the pothooks and hangers of some German urchin learning to write.
1862		E. de la Bédollière Londres et les Anglais 316/2: pothooks and hangers, griffonnage, mauvaise écriture.
1887		Isle of Wight Obs. 16 July 6/1: Written in an uncomfortable style [...] mixed and interspersed with pot-hooks and hangers, with an apostrophe turned into a full-stop.
1898		Aus. Town & Country Jrnl 4 Apr. 14: A msall girl who had spent a weary morning battling with pot-hooks and crooked S’s.
1908		Advertiser (Adelaide) 18 Dec. 8/9: He made me do pothooks for them, and said I couldn’t write my name.
1914		Public Ledger (Maysville, KY) 29 June 2/3: ‘Look at my copy, Teacher’ [...] Pothooks and worse than pothooks; scratches and blots galore.

2. (orig. Aus.) shorthand.

1885		Bulletin (Sydney) 28 Mar. 6/1: McDonnel, the Victorian cricketer, has, it is said, obtained a billet in N. S. Wales. In the letter resigning his Victorian Government appointment, he says: ‘It is but too apparent that there is no prospect for any junior in the service.’ This is not bad from a chap who passed in pothooks and hangers.
1901		Pacific Commercial Advertiser (Honolulu, HI) 13 Nov. 6/2: Pothook Expert [...] His skill at pothooks and hangers had much to do with his subsequent advancement.
1910		L.A. Herald 8 May 51/1: He was the youngest, greenest [...] reporter that ever scribbled pothooks and hangers.
1915		Sheffield Wkly Teleg. 21 Aug. 17/2: Pothooks and Hangers [...] an accomplished shorthand writer promised to tell her all the minister said.
1921		Challis Messenger (IO) 6 July 6/1: He had begged her toi teach him the art of shorthand [...] She handed him a nitebook [...] containing a neat array of pothooks and hangers.