Explaining the world one sketch at a time

Simplifying complex ideas through fun and insightful sketches. Explore topics from science, creativity, psychology, and more explained in pictures.

A weekly sketch by email

Learn something new in a sketch each Sunday

Recent sketches

A circle with a number of its mathematical parts labelled. And someone trying to climb up the tangent.

Parts of a circle

A recap of some of the fundamental parts of a circle, including some that are easy to forget: Diameter — a line crossing the circle through its centre. Also the longest straight line you can draw in a circle. Radius — a line from the centre to any point on the edge. Also, half the diameter. Sector — the classic Trivial Pursuit cheese, pizza or cake slice formed by two radii. Area — equal to pi x the radius squared. Circumference — equal to pi x the diameter. Arc — a section of the circumference. Chord — a straight line touching any two points of a circle. The longest chord is the diameter. Segment — the areas on either side of a chord, major and minor. Tangent — a straight line just touching the edge of the circle without crossing it. It forms a right angle to the radius on the edge. Just as if you were able to lean a ladder against one. More maths and science refreshers: States of matter, BODMAS (or PEMDAS), the 9 times table on your fingers, binary, incidence and reflection…A recap of some of the fundamental parts of a circle, including some that are easy to forget: Diameter — a line crossing the circle through its centre. Also the longest straight line you can draw in a circle. Radius — a line from the centre to any point on the edge. Also, half the diameter. Sector — the classic Trivial Pursuit cheese, pizza or cake slice formed by two radii. Area — equal to pi x the radius squared. Circumference — equal to pi x the diameter. Arc — a section of the circumference. Chord — a straight line touching any two points of a circle. The longest chord is the diameter. Segment — the areas on either side of a chord, major and minor. Tangent — a straight line just touching the edge of the circle without crossing it. It forms a right angle to the radius on the edge. Just as if you were able to lean a ladder against one. More maths and science refreshers: States of matter, BODMAS (or PEMDAS), the 9 times table on your fingers, binary, incidence and reflection

11 Dec 2022

Sharpen the saw

Sharpen the saw is a metaphor and story to remind us to refresh and recharge ourselves. When you're deep in, it may feel like you have no time to pause. No time to take a break, there's too much to get done. Perhaps no time to stop and think about how you're working. No time to step back and improve your processes or work on your tools. Maybe even no time to look after yourself, to recharge, to reflect, to take a walk. As the metaphor goes, you may feel you have no time to stop and sharpen the saw. Until you do it, and then you may realise you have no time to not stop and sharpen the saw. Sharpen the saw is habit 7 of Stephen Covey's classic The 7 Habits of Highly Effective People…Sharpen the saw is a metaphor and story to remind us to refresh and recharge ourselves. When you're deep in, it may feel like you have no time to pause. No time to take a break, there's too much to get done. Perhaps no time to stop and think about how you're working. No time to step back and improve your processes or work on your tools. Maybe even no time to look after yourself, to recharge, to reflect, to take a walk. As the metaphor goes, you may feel you have no time to stop and sharpen the saw. Until you do it, and then you may realise you have no time to not stop and sharpen the saw. Sharpen the saw is habit 7 of Stephen Covey's classic The 7 Habits of Highly Effective People

4 Dec 2022

Peeling away the intent and subtlety behind what seems a simple metric. Next to an onion.

The metrics onion

Metrics are like an onion: full of layers. A simple question to ask can often be complicated to answer. Or we may find that we need to ask a different question. While it'd be lovely to have one simple metric to understand our business the reality is usually a lot more nuanced and interesting than it first seems. Averages will deceive. Vanity metrics may wow — by, say, quoting a total user count and conveniently ignoring whether those users are actually paid, active, or leaving. Growth overall can hide declines in other areas or product lines and vice versa. The people on monthly subscriptions may be doing great, while revenue from add-ons may be declining. New users may be signing up in droves while existing users are churning. Mobile traffic may be different from desktop, online sales different from store sales... In practice, it's the hard questions we're usually asking even if we don't know how to ask them. It pays to carefully consider what you're trying to learn and to understand all aspects of a business before putting faith in the numbers. And it may make sense to start with simpler metrics first. Spend time with your data.…Metrics are like an onion: full of layers. A simple question to ask can often be complicated to answer. Or we may find that we need to ask a different question. While it'd be lovely to have one simple metric to understand our business the reality is usually a lot more nuanced and interesting than it first seems. Averages will deceive. Vanity metrics may wow — by, say, quoting a total user count and conveniently ignoring whether those users are actually paid, active, or leaving. Growth overall can hide declines in other areas or product lines and vice versa. The people on monthly subscriptions may be doing great, while revenue from add-ons may be declining. New users may be signing up in droves while existing users are churning. Mobile traffic may be different from desktop, online sales different from store sales... In practice, it's the hard questions we're usually asking even if we don't know how to ask them. It pays to carefully consider what you're trying to learn and to understand all aspects of a business before putting faith in the numbers. And it may make sense to start with simpler metrics first. Spend time with your data.

27 Nov 2022

Bus factor

The bus factor is how exposed you are if key people, perhaps with critical knowledge or skills, were hit by a bus. Examples might include the only people able to keep a company running, restore a server from a backup, or someone who held the only key to unlock crypto assets of its customers. As a result, many places are set up with, or required to have by investors or insurers, some redundancy — say two experienced developers with knowledge of how a service works — to minimise the risk of a tragic accident also being a severe problem for a company or its customers. As a metaphor, the bus factor may be helpful to consider without the need for people to actually be hit by a bus. It may be worth thinking through how you might operate if someone was late, missed their flight, was ill on the day, or simply quit. In operational roles, this will often lead to a minimum of two people for each key position if nothing else to allow one to take a break from time to time. An alternative framing, with fewer fatalities, is 'what if we all won the lottery?' and so decided to go do something else.…The bus factor is how exposed you are if key people, perhaps with critical knowledge or skills, were hit by a bus. Examples might include the only people able to keep a company running, restore a server from a backup, or someone who held the only key to unlock crypto assets of its customers. As a result, many places are set up with, or required to have by investors or insurers, some redundancy — say two experienced developers with knowledge of how a service works — to minimise the risk of a tragic accident also being a severe problem for a company or its customers. As a metaphor, the bus factor may be helpful to consider without the need for people to actually be hit by a bus. It may be worth thinking through how you might operate if someone was late, missed their flight, was ill on the day, or simply quit. In operational roles, this will often lead to a minimum of two people for each key position if nothing else to allow one to take a break from time to time. An alternative framing, with fewer fatalities, is 'what if we all won the lottery?' and so decided to go do something else.

20 Nov 2022

Ma sketch: a kayaker glides through a calm lake with a shoreline reflection on a moody grey day

Ma

Ma is the negative space — the space that makes the whole. Formed by the rather beautiful Chinese characters of 'Door' and 'Sun', like the sun gleaming through a doorway, it represents what isn't there and how that helps form what is. Ma is present in art, including beautiful minimalistic ink brush drawings and music where the silence and quiet that surround the notes help make a piece what it is. Some vintage-related sketches: figure and ground, use white space with care, John Cage Original ma sketch (without kayaker)…Ma is the negative space — the space that makes the whole. Formed by the rather beautiful Chinese characters of 'Door' and 'Sun', like the sun gleaming through a doorway, it represents what isn't there and how that helps form what is. Ma is present in art, including beautiful minimalistic ink brush drawings and music where the silence and quiet that surround the notes help make a piece what it is. Some vintage-related sketches: figure and ground, use white space with care, John Cage Original ma sketch (without kayaker)

13 Nov 2022

Two houses showing different approaches to heating: heating people and heating spaces

Heating people, heating spaces

With well-insulated houses and central heating as standard, I always grew up with heating the space as how you stay warm in the winter. A colleague once shared with me that where he'd lived, they thought of it as heating people, not spaces when looking to stay warm. The heating people approach means rather than heating the air in the room, you focus on heating the person: warm clothes, hot drinks, baths, cosy furniture with high backs and sides that traps heat in, or furniture that is itself heated like the kotatsu or aga, and generally local heating where a small room or even part of a room may be warm while the rest may be cool — dividing screens are sometimes used. This approach was common until relatively recently and also still is in countries where it was difficult to stay cool in the summer and houses weren't typically built to keep heat in. Thanks to Peter Wyatt-Brandenburg for sharing with me many years ago.…With well-insulated houses and central heating as standard, I always grew up with heating the space as how you stay warm in the winter. A colleague once shared with me that where he'd lived, they thought of it as heating people, not spaces when looking to stay warm. The heating people approach means rather than heating the air in the room, you focus on heating the person: warm clothes, hot drinks, baths, cosy furniture with high backs and sides that traps heat in, or furniture that is itself heated like the kotatsu or aga, and generally local heating where a small room or even part of a room may be warm while the rest may be cool — dividing screens are sometimes used. This approach was common until relatively recently and also still is in countries where it was difficult to stay cool in the summer and houses weren't typically built to keep heat in. Thanks to Peter Wyatt-Brandenburg for sharing with me many years ago.

6 Nov 2022

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