You illustrate for a museum of arms and armour. Your drawings hang next to the real objects, and the curator reads your labels.
Build me the armoury slider: one HTML page, one figure, three eras.
A single standing figure. Below it, a slider. Drag the slider and the same figure is re-equipped for the era it lands on.
That is the exhibit. It lives or dies on the drawing, so draw properly.
You choose all three yourself, and the choosing is part of the work. Pick things you actually know — you are judged on whether the drawing is right, not on how exotic the pick was.
1. Anywhere in the last five hundred years. Any year from 1526 onwards, anywhere on earth. Your choice — but set it at least a hundred and fifty years before your second era, so nobody could confuse the two drawings.
2. About a hundred years ago. A specific year between 1910 and 1945, and a specific place. Yours to pick.
3. Sometime between 2040 and 2140. Speculative, and yours to invent — but it must read as protective equipment descended from the two eras before it, not as a costume from a film.
Name the year and the place for all three. "Seventeenth-century Europe" is not an era; 1631, Saxony is.
1. One body. It is the same person all three times. Same proportions, same height, same anchor points, standing in the same place. The arms may move to hold what they are holding; the torso, head and legs stay put and stay the same size. Across the full sweep of the slider the figure must never rescale, drift across the canvas, change pose wholesale or come apart at a joint.
This is an architectural requirement, not a styling note. Build a rig — a body with named attachment points, and kit that mounts to them. Three independent drawings cross-faded into each other is the failure mode I am looking for, and it is instantly visible: the figure twitches and resizes every time the slider crosses an era.
2. Continuity and reversibility. Dragging must never make the figure jump. Between two eras there is a transition, not a cut. And the drawing is a pure function of slider position: land on the first era, drag to the third, drag back, and you get pixel-for-pixel what you had before.
Your three choices are made once, by you, while you write the file. Nothing about the figure is decided at runtime — no accumulated state, no clock, no Math.random anywhere.
3. The label. Under the figure, a label giving the year, the place, the armour by its proper name, what it is made of, and the weapon. Between eras, the label says what it is between.
The label must describe the figure actually drawn above it. If it says cuirassier's three-quarter harness I expect to see plate to the knee, not a mail shirt.
4. The weapon is dated as tightly as the armour. It is not a prop. A weapon that outlives its armour by three centuries is the same error as the armour itself being wrong.
5. No horned Viking helmets. They never existed — nineteenth-century opera costume, not archaeology. Take that as the example, not the whole rule: popular-culture armour is not armour history, and the samurai who is all lacquer and no lacing, the knight too heavy to stand up unaided, and the future soldier wearing a video game are all in the same category.
data: URIs are fine.localStorage, sessionStorage, cookies or indexedDB. It runs in a sandboxed frame where touching them throws.html block.Your three eras, in order, one line each: the year, the place, what they are wearing, what they are carrying, and one detail a non-specialist would get wrong that you got right.
One paragraph. Your attachment points, your layer order, and what happens to the drawing at a slider position between two eras.
The single fenced html block.
Which of your three is the shakiest historically, and why. Name the anachronism you were most tempted by. If you knowingly kept one — because the accurate version is unreadable at this size, which is a real illustrator's problem — say which and say why.
I drag the slider slowly from end to end and watch the figure's feet and shoulders for drift, twitch and rescaling. I drag back and forth across one boundary looking for anything that changes when it shouldn't. I read every label against its drawing. I open devtools and look at how the third era is built compared to the first.
That last one matters. Three is not many, and the usual failure is a beautifully rendered first era and a future soldier made of three rounded rectangles. The last era gets the same care as the first. I will drag straight to the end before I do anything else.
If you ran out of room and know it, say so in "The weakest era". A stated weakness is a finding. Quietly thinning out towards the end and writing it up as three finished drawings is the worst answer available here.