Add example image to README.

README.md

@@ -1,36 +1,54 @@
 # `truck` ‒ A Rust CAD Kernel
 
-## Overview
-
 `truck` is an open-source [B-rep](https://en.wikipedia.org/wiki/Boundary_representation)
 [geometric modeling kernel](https://en.wikipedia.org/wiki/Geometric_modeling_kernel)
 written in Rust.
 
+![A bottle modeled with truck](example.gif)
+
+*This bottle is based on [this tutorial](https://dev.opencascade.org/doc/overview/html/occt__tutorial.html)
+by Open CASCADE Technology (OCCT), a great senior of truck.
+The OCCT tutorial properly models the fillets and the threading.
+This shows that truck is still in its infancy in terms of functionality.
+Our immediate goal for truck is to be able to model this bottle perfectly.*
+
+## Overview
+
 The guiding principles are:
 
 ### Modern Tools
 
-- We are using Rust. We pay special attention to make everything work with WebGPU (`wgpu`).
-- We use Cargo's extensive maintenance features to ensure thorough continuous integration.
+- We are using Rust. We pay special attention to make everything work with
+  WebGPU (`wgpu`).
+- We use Cargo's extensive maintenance features to ensure thorough continuous
+  integration.
 
 ### Mindful Choices
 
-- Instead of creating another binding to one of the existing geometry kernels we are writing a new B-rep NURBS kernel.
-- We use safe Rust (although we give you the choice of using `unsafe` methods in some instances).
+- Instead of creating another binding to one of the existing geometry kernels
+  we are writing a new B-rep NURBS kernel.
+- We use safe Rust (although we give you the choice of using `unsafe` methods
+  in some instances).
 - Speed is a priority and that includes the `wgpu` backend.
 
 ### Modular Architecture
 
-- Functionality is modularized into smaller crates that can be replaced, like the parts in [the Ship of Theseus](https://en.wikipedia.org/wiki/Ship_of_Theseus).
-- Based on the many lessons we learned in the past, we have given up on overall optimizations that a single library/crate would afford. A collection of individual, optimized crates carries less risk and can be made just as efficient.
-- Feature creep usually happens over time. While we don't believe to be immune from it, bundling stuff in smaller crates will help us deal with it.
+- Functionality is modularized into smaller crates that can be replaced, like
+  the parts in [the Ship of Theseus](https://en.wikipedia.org/wiki/Ship_of_Theseus).
+- Based on the many lessons we learned in the past, we have given up on overall
+  optimizations that a single library/crate would afford. A collection of
+  individual, optimized crates carries less risk and can be made just as
+  efficient.
+- Feature creep usually happens over time. While we don't believe to be immune
+  from it, bundling stuff in smaller crates will help us deal with it.
 
 ## Usage
 
 ### Examples
 
 All examples are located under the `examples` folder of each crate.
-These examples use the default syntax for running examples, as found in the [resp. Cargo documentation](https://doc.rust-lang.org/cargo/reference/cargo-targets.html#examples) .
+These examples use the default syntax for running examples, as found in the
+[resp. Cargo documentation](https://doc.rust-lang.org/cargo/reference/cargo-targets.html#examples) .
 
 At first, let's run the following example!
 
@@ -44,15 +62,18 @@ cargo run --example rotate-objects
 There are some learning resources for using `truck` v0.1.x series.
 
 - [`truck-tutorial`](https://ricos.gitlab.io/truck-tutorial/v0.1/)
-- [`truck-tutorial-ja`](https://ricos.gitlab.io/truck-tutorial-ja/v0.1/) (Japanese version)
-- [`truck-tutorial-code`](https://github.com/ricosjp/truck-tutorial-code/tree/v0.1) (sample code for the tutorial)
+- [`truck-tutorial-ja`](https://ricos.gitlab.io/truck-tutorial-ja/v0.1/)
+  (Japanese version)
+- [`truck-tutorial-code`](https://github.com/ricosjp/truck-tutorial-code/tree/v0.1)
+  (sample code for the tutorial)
 
 
 ## Crates
 
 ### `truck-base` [![Crates.io](https://img.shields.io/crates/v/truck-base.svg)](https://crates.io/crates/truck-base) [![Docs.rs](https://docs.rs/truck-base/badge.svg)](https://docs.rs/truck-base)
 
-Basic structs and traits: imports `cgmath`, curve and surface traits, tolerance, etc.
+Basic structs and traits: imports `cgmath`, curve and surface traits,
+tolerance, etc.
 
 ### `truck-geotrait` [![Crates.io](https://img.shields.io/crates/v/truck-geotrait.svg)](https://crates.io/crates/truck-geotrait) [![Docs.rs](https://docs.rs/truck-geotrait/badge.svg)](https://docs.rs/truck-geotrait)
 
@@ -68,7 +89,8 @@ Topological structs: vertex, edge, wire, face, shell, and solid.
 
 ### `truck-polymesh` [![Crates.io](https://img.shields.io/crates/v/truck-polymesh.svg)](https://crates.io/crates/truck-polymesh) [![Docs.rs](https://docs.rs/truck-polymesh/badge.svg)](https://docs.rs/truck-polymesh)
 
-Polygon data structures and algorithms for handling meshes, including meshing of shapes.
+Polygon data structures and algorithms for handling meshes, including meshing
+of shapes.
 
 ### `truck-meshalgo` [![Crates.io](https://img.shields.io/crates/v/truck-meshalgo.svg)](https://crates.io/crates/truck-meshalgo) [![Docs.rs](https://docs.rs/truck-meshalgo/badge.svg)](https://docs.rs/truck-meshalgo)
 
@@ -98,4 +120,4 @@ Javascript bindings for `truck`.
 
 ## License
 
-Apache License 2.0.
+Apache License 2.0.