{"slug": "postscriptum-on-llms-pelicans-on-bicycles-with-a-twist", "title": "Postscriptum on LLMs: pelicans on bicycles with a twist", "summary": "Danilo Segan tested frontier LLMs' ability to generate native PostScript images of a pelican riding a bicycle, finding that models like Gemini 3.7 Flash and Opus 5 required multiple iterations and error corrections, with Opus 5 improving over four cycles. The experiment suggests that LLMs lag in less common vector formats compared to SVG, as Segan expected.", "body_md": "## Judge Dread? Or welcome to my first LLM-related post.\n\nAs LLMs and especially coding agents became part of our daily workflows,\nwe started relying more on actual *judgement* of models\nwe use — judgement, to me, is any decision they default to based on\ntheir training and pre-processing without humans actually directing\nthem with prompts or skills.\n\nIt might be a simple decision about using tabs or spaces, or\na more complex one about how to structure your tests and test\nfixtures, but you can already get a lot done by offloading\n*decision-making* as well.\n\nWhile this is fast improving, I wanted to test *my*\nunderstanding by asking them to do an extremely common test by\nSimon Willison of generating a vector image of a\n[pelican riding a bicycle](https://simonwillison.net/tags/pelican-riding-a-bicycle/\n),\nbut **with a twist**: instead of asking for an SVG,\nask for a conceptually different vector format\n[PostScript](https://paulbourke.net/dataformats/postscript/) (really, a programming language), which is\ncloser to the plotting/printing model from 80s, with instructions\nlike `moveto`\n\n, Y-axis actually going upwards, for loops,\nmatrix transformations etc — enough difference in semantic\ninterpretation and less training data to throw a frontier model off :)\n\nMy expectation was that they would be a generation or two behind compared to what Simon is getting with SVGs.\n\nI'll let you be the judge if my foresight was right or not.\n\nPrompt: *Generate a native PostScript image of a pelican riding a bicycle.*\n\n## Some quick notes\n\n- I tried converting PostScript files with ImageMagick first, but after seeing it miss a few things during conversion, decided to use GhostScript loader from within Inkscape instead and export a PNG out.\n- Gemini 3.7 Flash had a broken first version which it was able to fix with the Ghostscript error message passed back (I think it was wrong parameters for ellipse command).\n- Opus 5 took around 4 iterations of rendering to a raster image and reviewing (also hitting a PS syntax error), but managed to improve with each cycle. I did not check the costs, but it was probably expensive :)\n- My first few attempts were with a slightly different prompt of \"Make an PS or EPS (PostScript) of a pelican riding a bicycle\" (\"an\" typo included — I probably went for EPS first and never corrected the language). This resulted in\n*greyscale*images in ChatGPT confirming that this might be worth looking into. I did not approach it scientifically at all, but switching to \"Generate\" to match Simon's version always produced a colorized version. - All of the text in this post was hand-typed, including the em-dashes.\n\n[21:19](https://danilo.segan.org/blog/2026/Aug/29#postscript-pelicans-on-bicycles)] | [\n\n[] |](https://danilo.segan.org/blog/)\n\n[#](https://danilo.segan.org/blog/llm/postscript-pelicans-on-bicycles)|\n\n[G](https://www.google.com/search?q=Postscriptum on LLMs: pelicans on bicycles with a twist)|\n\n[|](https://danilo.segan.org/blog/llm/postscript-pelicans-on-bicycles#comments)\n\n[TB](/blog/trackback/llm/postscript-pelicans-on-bicycles)", "url": "https://wpnews.pro/news/postscriptum-on-llms-pelicans-on-bicycles-with-a-twist", "canonical_source": "https://danilo.segan.org/blog/llm/postscript-pelicans-on-bicycles", "published_at": "2026-08-29 21:22:55+00:00", "updated_at": "2026-08-29 21:48:41.154123+00:00", "lang": "en", "topics": ["artificial-intelligence", "large-language-models", "generative-ai"], "entities": ["Danilo Segan", "Simon Willison", "Gemini 3.7 Flash", "Opus 5", "PostScript", "GhostScript", "Inkscape"], "alternates": {"html": "https://wpnews.pro/news/postscriptum-on-llms-pelicans-on-bicycles-with-a-twist", "markdown": "https://wpnews.pro/news/postscriptum-on-llms-pelicans-on-bicycles-with-a-twist.md", "text": "https://wpnews.pro/news/postscriptum-on-llms-pelicans-on-bicycles-with-a-twist.txt", "jsonld": "https://wpnews.pro/news/postscriptum-on-llms-pelicans-on-bicycles-with-a-twist.jsonld"}}