A few years back before computers
(yes there was a time before computers) us arty types had to produce visuals to present to the client, men in suits or the guy or girl that was hopefully paying the bill. The only way to do it was by hand, yes I know what you are thinking, you had to DRAW it.
Sketched out on real paper, the marker or layout pad, no digital fancy ipaddy and wacky dacom tablet then. I had to sketch it down with a HB pencil and a black fine liner from the model sitting in front of me.
Once the drawing was complete it was time to render it as the professionals used to say, I used to prefer "colouring it in".
This was achieved with the help of the "magic marker", a truly wondrous tool which was basically a wad of cotton like material (felt) soaked in alcohol based pigmented colour with a hard chiseled tip in a small glass holder (yes the originals were glass I kid you not) with a screw top - The ultimate felt tip pen!
These were available to buy in well over 150 different colours and were the number one choice for visualisers and designers. But boy they were expensive, so I used to try and make my own from pure alcohol and beetroot, vinegar ,tea and anything else that would stain and have intense colour. This was fantastic exploration but led to some of the most evil smelling, stinking visuals I have ever done.
Come to think of it, I invented Scratch n' Sniff before it came famous!!
The beauty of them was that eventually after LOTS of practice you could really control the depth and application of colour and it became second nature. You couldn't just delete the layer or command z if you made a mistake though, sometimes you just had to start again, so it taught you how to get it right first time. Eventually the glass holder disappeared and was replaced by plastic with a thin and a thick tip either end for even more control.
Anyway here is one of hundreds of visuals that I have created, hand drawn, with just magic markers.
The downside was that LEGO has sooooo many studs it drove me nuts!!