Creator: Enrico Tartarotti · Published: 2025-12-05 · Length: 14:09 · Watch on YouTube

Why isn't dark mode actually black? Why aren't iPhone icons rounded rectangles? What's really happening when you zoom in and out on Google Maps? (from the video description)

Enrico says years of building tech have left him with "weird niche knowledge" of the tricks and hidden decisions behind everyday software. He takes the viewer three levels deep: the surface you see, the thousands of details most people never notice, and the complex systems behind even the simplest interactions, with the warning that it "might break the magic." Sponsored by Snapchat Lens Studio. Written and produced by Enrico Tartarotti; edited by Seequence Studio.

Summary written from the auto-generated captions, the video description and the creator's chapter markers. Many examples are shown on screen, so descriptions of visuals are inferred from the narration.

1) Detailed outline

[0:00] Intro: the space bar with no pop-up

• Phone keyboards show a pop-up for each letter you press, standing in for the feel of a physical key and confirming you hit the right letter on a tiny keyboard.
• On both iOS and Android, the space bar has no pop-up. It was deliberately turned off because it's the most-used key (constant pop-ups would be annoying) and big enough that mistakes are rare. Someone had to program that exception by hand.
• That detail, which 99% of people never notice, opens a rabbit hole. Enrico lays out the three levels and warns the video may make you over-analyze everything "like a crazy person like myself."

[1:22] Level 1: what you see on the surface

• The two-state problem. A video player's pause button shows a pause icon while playing and a play icon while paused: the icon shows what happens when you click. Google Meet's mute button is the reverse: the icon shows the current state, not the future one. Enrico shows a user who panicked in a conferencing tool because he couldn't tell whether his mic was live.
• Fixes: separate the status from the action, as the Tesla app does (a lock icon shows the car's state, and a button switches to the other state), or use clear colors and shapes for the state, as the iPhone call screen does when you mute.
• Design patterns. Three plain items mean nothing until you add shapes around them. Rounded rectangles turn them into tabs, so you know in 0.1 seconds that "skiing" is active and tapping another switches content. A different grouping says skiing and volleyball are switchable but biking is separate. Other treatments read as tags (properties of some other element) or as on-off toggles. The content never changes; only the surrounding pattern does, and that's what makes tech usable without a manual.
• The ellipsis. The three-dot "more options" icon comes from books, where dots signal that a list continues. Writing can get away with two dots, but tech always uses three: menus are often vertical, two dots would look like a colon, and four would be too cluttered.

[3:43] Level 2: the details most people never notice

• The blinking cursor blinks so you can find it while you're idle, but stays solid while you type, because blinking then would be distracting.
• Form validation. If an email field checked validity on every keystroke, it would scream "invalid" after the first few letters. So email checks run when you defocus the field (you're done typing). A password with a minimum length is the opposite case: there you check on every keystroke, since waiting for defocus would be annoying.
• These details are "the difference between a product that feels good and one that makes you want to throw your laptop out the window."
• Small touches. Some editors replace a typed dash plus greater-than sign with a real arrow symbol "just because why not."
• Reply toggles. On YouTube, the toggle to expand comment replies stays in place and the replies appear below it, because the intent is to glance at the top replies and close them; two clicks open and close. On Instagram, the collapse button sits under the replies, so you have to scroll down to close them. At billions of daily users, Enrico suggests, that could be why YouTube users check replies more and comments see more discussion.
• Dark mode and OLED. Wiggle the iPhone Calculator on an OLED screen and the gray buttons seem to lag. On OLED, black pixels turn off completely and take slightly longer to turn back on than pixels switching between colors, which smears moving content. So dark-mode apps shouldn't use pure black backgrounds, especially with scrolling content ("Yeah, I'm looking at you, X").
• Color banding. In his own company's product, Flask (a video-collaboration tool), a subtle radial "glow" gradient in the comment box showed blocky bands because there weren't enough colors between the start and end shades. He fixed it by stacking four or five elliptical gradients on top of each other.
• Rounded corners everywhere. Besides being hard to render in the 80s, sharp corners read as danger (blades, weapons), and nature has few perfect angles. Rounding makes elements feel approachable, less threatening and more playful.
• Squircles. Apple app icons aren't rounded rectangles but squircles, a shape between a circle and a square that feels more organic. Now Apple's whole UI, including the iPhone's physical corners, uses squircles so everything stays concentric and aligned.

[8:13] Sponsor: Snapchat Lens Studio

• Enrico cites the internet's 90-9-1 idea: 90% of people consume, about 10% comment and engage, and 1% create, and that 1% changes things for everyone else.
• In Lens Studio he recreates the yellow hat he used to wear in old videos as a real-time Snapchat AR filter and publishes it as a lens anyone can use. Lenses can also be generated by chatting in natural language.
• What excites him is depth: it's a full platform for augmented-reality experiences, and developers have built complex games and lenses used by millions. It's free on desktop and iOS.

[9:30] Level 3: the complex systems behind simple interactions

• Zooming in Google Maps (Tokyo). As the map zooms, text and icons stay the same size, so an algorithm constantly checks whether labels or icons would overlap and hides the colliding ones. It works dynamically, accounting for things like how long a place name is, not just the zoom level.
• Relevance. Some places stay visible far past their zoom level because a real-time system judges them more relevant to you right now.
• Hierarchy. Historical sites and landmarks outrank local points of interest (as inside the Imperial Palace grounds), and some neighborhood names, such as one in Chiyoda city, keep showing when zoomed far out.
• Contrast. Zoomed in, street names are white because there's enough gray asphalt around them for contrast. Zooming out, they first invert color to stay legible against thinner roads, then disappear.
• The exception. Your pinned locations are allowed to overlap, since showing all of them is the point.
• Extras nobody needed. Zoomed all the way out, the globe shows the orange shading of sunrise and sunset. When Enrico posted this on X, a Google Maps engineer replied that the stars in the background are accurate constellations, not random dots.
• Google Photos day grouping. Photos from a night out in Tokyo taken at 1:24 a.m. Saturday are grouped with Friday's photos, because someone built a grouping system that keeps a night out under its starting date, to feel more human.
• X preloads links. A page with a timer showing how long it's been open reveals it was already loaded before he tapped the link: X opens and pre-renders pages in the background so they appear instantly. Good for speed, but Enrico isn't comfortable with pages loading on his phone before he clicks, calling it "potentially dangerous."
• Optimistic updates. Most apps send an action (like posting a tweet) to the server and wait for confirmation, so you see spinners or a one-second lag. Snappy apps assume the action succeeded, update the UI instantly, sync with the server in parallel and only tell you if something fails. Google Docs autosave works this way.

[13:47] Outro

• The last layer isn't about how tech works but a story: how Silicon Valley spent the past ten years stripping the fun and playfulness out of tech, and how things are starting to get weird again. He points to his video How Silicon Valley KILLED Fun.

2) Things mentioned

Apps and products

• iOS and Android keyboards (space bar with no key pop-up)
• Google Meet (inverted mute icon)
• Tesla app (separate lock status and lock button)
• iPhone call screen mute state, iPhone Calculator on OLED, iPhone squircle corners
• YouTube comment-reply toggle versus Instagram's
• X (pure-black dark mode, link preloading, where Enrico posted the Maps discovery)
• Flask, Enrico's video-collaboration tool (gradient banding fix)
• Google Maps (Tokyo label collision, relevance, hierarchy, sunrise and sunset shading, accurate stars)
• Google Photos (late-night photos grouped under the previous day)
• Google Docs (autosave via optimistic updates)
• Snapchat Lens Studio (sponsor; AR lenses, natural-language lens creation, free on desktop and iOS)

Design patterns and UI details

• The two-state problem (icons showing state versus action)
• Separating status from action; using color and shape for state
• Tabs, segmented groups, tags and toggles as design patterns
• The three-dot ellipsis menu and why it's always three dots
• Blinking versus solid typing cursor
• Validate-on-defocus (email) versus validate-per-keystroke (password length)
• Auto-replacing "->" with an arrow symbol
• Reply-toggle placement and its effect on engagement
• Rounded corners and why sharp shapes feel threatening
• Squircles in Apple icons and UI

Display and rendering

• OLED black-pixel smearing and why dark mode shouldn't be pure black
• Color banding in subtle gradients, fixed by stacking elliptical gradients

Systems and engineering

• Map label collision detection and dynamic hiding
• Real-time relevance ranking and place hierarchy
• Contrast-aware street-name color inversion
• Pinned locations as an overlap exception
• Human-friendly photo grouping by "night out" rather than calendar day
• Link preloading and pre-rendering (with privacy concerns)
• Optimistic updates versus waiting for server confirmation

Places and ideas

• Tokyo, the Imperial Palace, Chiyoda city
• The 90-9-1 rule of internet participation
• Next video: How Silicon Valley KILLED Fun

3) Biographies

Enrico Tartarotti

Italian-born YouTuber, designer and entrepreneur whose channel goes "behind the scenes of the design and psychology and stories behind the tech you use everyday." He builds Flask, a video-collaboration tool he uses as a live example in this video, and writes and produces his videos, which are edited by Seequence Studio.

Google Maps engineer (unnamed)

An engineer on the Google Maps team who replied to Enrico's post on X to point out that the stars shown when you zoom all the way out are real constellations. Enrico doesn't name them in the video.