"Draw what?" they'll ask.
The engine is running, the pistons are pumping, but the clutch is engaged, so they're not going anywhere. Facing a blank slate of possibility, there is no decision to be made, no problem to be solved, the brain cries out for input and waits. Few people can put the pencil to paper with the only instruction being to draw. But if you want someone to draw a house, or a cat, or a bowl of fruit, the clutch releases and now the brain has a problem to solve, decisions to make. How big is the house, what color is the cat, how many bananas in a bunch? Questions are instantly asked and answered by the brain as it begins cogitating around the idea of what it is supposed to draw, and then attempts to bring those answers to bear on the paper.
I often get the feeling that the brain functioning like this is something like an internal wikipedia. See, when I think house, it doesn't just mean house. There's a link to walls, there's a link to a roof, there's a link to basements and second stories, to windows and curtains, to fireplaces and chimneys, yards and gates, driveways and streets, suburbs and cities, addresses and zip codes, and on and on. There's the idea of the house, but you can't fully understand what that represents, without understanding everything that's collectively associated with that thing, and associated with those things as well, and on and on. The cognitive functions of the brain are like massive spider webs of neuron connections, tracing routes that are unique to your experiences, constantly flowing down these pathways, making new links all the time. The brain abhors a blank slate as it were. It wants to connect things, like electricity, it wants to flow down a path of least resistance, and put ideas into pre-established channels.
It can easily forge new pathways if it has to, but predominantly, it simply wants to use the ones already established if it can. Many optical illusions and tricks of the mind play on this fact. They prey on the fact that your brain will most often follow a preset path when presented with a certain set of circumstances, and amaze you by simply altering a small but insignificant detail that changes the entire experience. That newness, and sense of amazement is your brain trying to run down its same pathways, and finding them lacking a significant connection to explain what it is attempting to comprehend. But the brain is stimulated, it's excited, it has a problem to solve, and connections to establish to explain away this enigma that it has been presented.
But when you have no illusion, no trick, just an empty piece of paper to fill. The brain is frustrated. It has no synapses to fire, no neuron pathways to follow. It waits patiently for input.
"Draw what?" it asks.
Complete freedom of choice in the thought process above is like looking at a blank web page, with only a search box sitting there in the middle, cursor blinking steadily in your face. There are no ideas there. No explanations of things with associated links to click. Just an empty space, waiting for you. Blink. Blink. Blink.
One of the most frustrating experiences a writer can have, is staring at that blank page, with only the intention to write. No idea what to write, just that writing needs to be done, and it isn't getting done. The trick you hear about is to just start writing, about anything, and sooner or later you'll get passed it. Honestly, I've had a hard time doing that, so the trick I've learned, is about restrictions. If you stare at the page, with no idea what you want to put down, clutch engaged. But if I say, "I'm going to write about cars", we're off, and I'm thinking about makes, models, colors, tires, body kits, engines, transmissions, et al.
I remember in one of my old college creative writing classes, we had a freeform assignment due, and my partner could not get past the first sentence. Complete writer's block. After a day of this he told me what he was going through.
I asked him if he could write me a couple of paragraphs, and picking ideas randomly, I said it should be about a man in a park, coping with the loss of his wife, while feeding birds. He looked at me weird, and asked why he would write something like that. But I asked him if he could see the story, the details, and he said he could probably come up with some. So I started to ask more questions.
I asked how old the man was. He said older, 60 something.
I asked what kind of trees were in the park, and he said giant maple trees, with lots of shade around them, but bright and sunny outside of the reach of their branches.
I asked him where he was sitting, and he said on a bench, under a one of those trees, in the shade, with pigeons around him, but the pigeons were in the sunlight.
I told my friend he didn't have writer's block. He just needed an idea. An idea that his brain could latch onto and begin questioning itself about the details. That what was stopping him was simply that he had so many choices on what to write for his project, that he couldn't cope with that complete freedom, and he was simply stuck in nowhere trying to find a way out. To fix it, he just needed to settle down on an idea, an object, something, and then once his brain had latched on to it, extrapolate. Explore the connected pathways that are associated with that idea, and from there you can begin. Those connections are really the key towards building a story, towards painting a picture, towards writing a poem.
The key to creating something... from nothing.
If you find yourself having trouble coming up with something to write, or draw, or create. Do what I do, and find a random word generator, and get six words, and start thinking of what they mean, and how they could relate to each other, and go from there. Words like: