Simplify & polish

docs/demos.md

 
 # WebAR demos
 
-Welcome to my demo gallery! Here you'll find some cool examples of what you can do with MARTINS.js. Feel free to adapt my demos and also to study my code.
-
-!!! info "Derivative works"
-
-    The Free Edition of MARTINS.js is included with my demos. Before creating derivative works of my demos, make sure to [pick the right edition for you](./download.md){ ._blank }.
+Welcome to my demo gallery! Here you'll find some cool examples of what you can do with MARTINS.js. Feel free to adapt my demos and also to study my code. The Free Edition of MARTINS.js is included with my demos. Before creating derivative works of my demos, make sure to [pick the right edition for you](./download.md){ ._blank }. If you have any questions, feel free to [reach out](./contact.md){ ._blank }.
 
 ## Free demos
 
 <a href="https://ko-fi.com/s/25f4038f8b" rel="external" target="_blank">
 
 
-![](./img/demo-webgl.jpg)
+![](./img/logo-webgl.png)
 
-**Render with WebGL (3D)**
+**WebAR with WebGL + MARTINS.js**
 
 </a>
 </div>
 
 ![](./img/logo-aframe.png "A-Frame logo by Mozilla")
 
-**AFRAME + MARTINS.js**
+**WebAR with AFRAME + MARTINS.js**
 
 </a>
 </div>
 
 ![](./img/logo-threejs.png "Three.js logo by Mr.doob")
 
-**THREE.js + MARTINS.js**
+**WebAR with THREE.js + MARTINS.js**
 
 </a>
 </div>
 
 ![](./img/logo-babylonjs.png "Babylon.js logo by David Catuhe")
 
-**BABYLON.js + MARTINS.js (soon)**
+**WebAR with BABYLON.js + MARTINS.js (soon)**
 
 </div>
 </div>
 <a href="https://ko-fi.com/s/1d3c7e401c" rel="external" target="_blank">
 
 
-![](./img/demo-interactivity-three.jpg)
+![](./img/logo-threejs.png)
 
 **Touch interaction with THREE.js**
 

docs/download.md

 
 ### Is it free of charge?
 
-In a nutshell: it's free of charge if you write free software.
+It's free of charge if your software is also free.
 
 The Free Edition is unsuitable for most commercial users. It's [AGPL](./license/agpl-3.0.md)-licensed: any software written with the Free Edition must be free as well. If you write non-free software, use the Professional Edition instead.
 
-You may use the Professional Edition to create various kinds of commercial, proprietary AR experiences. However, you may not sublicense it nor transfer your license to anyone. Additionally, you may not use it to create any product that competes with this software, not even a "as-a-service" style of product (e.g., SaaS). Please read the [license](./license/PolyForm-Perimeter-1.0.0-1.md) for more information.
+You may use the Professional Edition to create various kinds of commercial, proprietary AR experiences. However, you may not sublicense it nor transfer your license to anyone. Additionally, you may not use it to create any product that competes with this software, including a "as-a-service" style of product (e.g., SaaS). Please read the [license](./license/PolyForm-Perimeter-1.0.0-1.md) for more information.
 
 ### Where can I ask questions?