The 1,000 Floor Elevator: Why Most Designers Fail Google’s Infamous Interview Design Challenge

Jun 21, 2017 · 5 min read

Design challenges are nothing new- plenty of companies use them in order to assess potential employees’ problem solving skills. But a Google interview challenge in particular seems to have captivated the global design community:

Designers from around the world have taken stabs at the question; there are dozens of articles, diagrams, projects and sketches online, attempting to solve the 1,000 floor elevator interface:

Images by Jherin Miller
Aayush Jain
Images by Kristine Yuen
Images by Aayush Jain

Yet virtually all solutions I’ve encountered fail almost immediately for the exact same reason…

The Presumption Reflex

If a friend says “I’m going to the movie theater” we automatically presume she’s going to watch a movie, because personal experience tells us that’s the main reason people visit theaters. But it was never stated she’s actually going to watch a film. However unlikely, she may be meeting up a friend or just really likes overpriced Skittles. When given a scenario, we have a tendency to conclude outcomes that seem reasonable to us.

It is precisely this cognitive reflex that we as designers have to fight against, and the very first line of defense is questioning, as experienced designers always have more questions than answers.

Let’s tackle the challenge

Before we get to the 1,000th floor, we need to start with the foundation- uncover constraints and obtain greater context. Let’s start with the…

Let’s say it’s a biggish elevator, can hold around 50 people, probably has a few seats for taking rest, and a TV screen” -random online solution

When we think of an elevator, our personal experience recalls all the times we’ve rode in one, so our presumptive reflex tells us that elevators are used by people. But what if the elevator in question is for transporting animals, cars, or washing machines?

Nearly all solutions made this mistake and designed a human-centric interior equipped with TVs, NFC card readers and directories, without knowing if it will be used by people:

Images by Kristine Yuen
Images by Kristine Yuen

“Who lives here?
A 1000 floor building is potentially a whole city living inside a mega structure, so it is feasible there is everything a city needs (parks, schools, playgrounds, hospitals, theaters etc) within the building.” -random online solution

The second presumptive mistake is assuming that the building is inhabited by people as well. Once again, nothing suggests that there are any residential or commercial spaces, yet solutions included searchable directories of the building’s imaginary residents:

Images by William Clark

Why assume that the building is not a parking garage for cars or an industrial warehouse for washing machines?

This line of questioning quickly leads us to the realization that we don’t know who the users are or what their needs might be. Is the interface meant for elevator passengers on the way to their apartment or operators who control multiple industrial elevators in a washing machine factory control room? Is there even a need for an interface in the first place? Could it be automated?

Perhaps more worrisome than making presumptions blindly, is to make them consciously. Many proposed solutions start out by stating the very assumptions they’re making in hopes of absolving themselves of fallibility:

“Assumptions Made In This Scenario

-Each residence or business is provided with an appropriate amount of keychains

-There is a security desk at the lobby

-The buildings would need to be at least a dozen or so blocks wide to have a solid foundation…”

-random online solution

This misses the point entirely. If we start making up arbitrary constraints, this is no longer a design challenge- it becomes an exercise in imagination. Why not just presume the elevator can read brainwaves, thus eliminating the need for an interface all together? Because that’s an equal of a leap as assuming the elevator will be used to transport people in the first place. The truth is that at this stage, there is only one correct response:

Potential employers don’t pose design challenges with the expectation that you blow them away with your ingenuity or clever solutions. They want to see if you ask probing questions that uncover constraints, or if you rush to the whiteboard without deeper understanding. Being a designer means fighting the presumptive reflex, which takes disciplined reasoning and self awareness in order to truly understand the context of a problem. Although there is no guaranteed way to pass any given design challenge, the surest way to fail is to offer answers before questions.

My concepts, designs & inventions

Svilen's Realm

I invent, design and craft experiences and solutions ranging from reimagining the mundane to protecting fundamental human rights. I share my visions with the world through the language of design, film, and writing.


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Speculative Designer | creator of &

Svilen's Realm

I invent, design and craft experiences and solutions ranging from reimagining the mundane to protecting fundamental human rights. I share my visions with the world through the language of design, film, and writing.