Most people fail the written permit test on signs they "knew" — because they studied the picture, not the silhouette.

On the real exam you often get a black shape with no icon. If you cannot name it from the outline, you miss it.

Both Rwanda and the US

• Octagon → STOP. Full stop. No rolling.

• Inverted triangle → yield / give way.

• Circle with a red ring (Vienna / Rwanda) → prohibition or a speed limit in km/h.

• Diamond (US) → warning. Slow down and look for the hazard.

US-only traps

• Pentagon → school zone or school crossing.

• Yellow pennant on the left side of the road → no-passing zone.

• Round yellow → railroad crossing ahead, not a roundabout.

Rwanda-only habit

A number inside a red circle is a limit in km/h. Do not convert it to mph in your head on test day.

Color is the second pass: red = stop/prohibit, yellow = warning, orange = work zone, blue circle (Vienna) = you must do this.

Study the shape table until you can cover the icon with your hand and still name the sign. Then open your country handbook (Irembo / your state DMV PDF) and confirm the local numbers — ages, fees, pass marks. Those change. Shapes do not.

Most home coffee fails for one reason: the grind is wrong for the method, and people "fix" it by buying a new bag.

Sour, sharp, tea-like → under-extracted. Grind finer, or give it more time.

Bitter, ashy, drying → over-extracted. Grind coarser, or shorten the brew.

Weak but otherwise fine → you need more coffee, not a finer grind. Start at 1:16 (18g coffee to 288g water).

The other thing that kills cups: grocery beans with a best-by date and no roast date. Buy whole beans roasted in the last two weeks. Grind right before you brew.

If you want the full system — gear worth buying, pour-over / press / AeroPress recipes, and a 5-minute weekday ritual — it's in Perfect Coffee at Home.

People spend $400 on a machine and keep a blade grinder. That is why their coffee still tastes like the office.

The cup is decided before water hits the grounds:

• Beans with a roast date, not a best-by date. Finish the bag in 3 weeks.

• A burr grinder. Even a hand grinder. Uneven grind is sour and bitter in the same sip.

• A scale. 18g coffee to 300g water. Scoops lie.

• One brewer. AeroPress, V60, or French press. Not all three.

If the cup is sharp and sour, grind finer. If it is dry and ashy, grind coarser. Change one thing per brew.

That loop — not a chrome machine — is how you make cafe coffee at home.

I put the full system (methods, tasting, a 5-minute weekday routine) in Perfect Coffee at Home.

Most bad coffee at home is not the beans. It is guessing.

Use 1 gram of coffee to 16 grams of water. For a normal mug that is 18g coffee and 288g water, medium-fine grind, water just off boil, about 3 minutes in a pour-over.

If the cup is sour, grind finer. If it is bitter, grind coarser. Change only that. Do it five mornings in a row before you touch anything else.

A $15 dripper and a scale will beat a machine you do not know how to use. The rest is showing up.