Generate and check-in icons

Checking in icons is not super pretty git practice, but when rendering
through GitHub, that's the easiest option

.icons/app.png.license

@@ -0,0 +1,3 @@
+SPDX-License-Identifier: CC-BY-3.0
+SPDX-License-CopyrightText: delapouite
+Original file from https://game-icons.net/1x1/delapouite/keyboard.html

.icons/board.png.license

@@ -0,0 +1,3 @@
+SPDX-License-Identifier: CC-BY-3.0
+SPDX-License-CopyrightText: lorc
+Original file from https://game-icons.net/1x1/lorc/circuitry.html

.icons/module.png.license

@@ -0,0 +1,3 @@
+SPDX-License-Identifier: CC-BY-3.0
+SPDX-FileCopyrightText: lorc
+Original file from https://game-icons.net/1x1/lorc/jigsaw-piece.html

.icons/rebuild.py

@@ -0,0 +1,24 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: CC0-1.0
+# SPDX-FileCopyrightText: chrysn <[email protected]>
+# /// script
+# dependencies = ["cairosvg"]
+# ///
+
+import urllib.request
+import cairosvg
+
+game_icons = {
+        "board": ("lorc", "circuitry"),
+        "app": ("delapouite", "keyboard"),
+        "module": ("lorc", "jigsaw-piece"),
+        }
+
+for (outname, (author, iconname)) in game_icons.items():
+    svg = urllib.request.urlopen(f"https://game-icons.net/icons/ffffff/000000/1x1/{author}/{iconname}.svg").read()
+    outname = outname + ".png"
+    cairosvg.svg2png(bytestring=svg, write_to=outname, output_width=20, output_height=20)
+    with open(outname + ".license", "w") as licensefile:
+        print("SPDX-License-Identifier: CC-BY-3.0", file=licensefile)
+        print(f"SPDX-License-CopyrightText: {author}", file=licensefile)
+        print(f"Original file from https://game-icons.net/1x1/{author}/{iconname}.html", file=licensefile)

README.md

@@ -23,12 +23,23 @@ As part of the RIOT project, the [RIOT code of conduct] applies.
 Projects using RIOT OS
 ----------------------
 
-* RIOT in space: [ThingSat.space](https://github.com/thingsat/) is using RIOT on CubSats to create an open source Low Power Global Area Network (LPGAN)
-* [MiniLoon](https://www.hackster.io/386121/miniloon-60a9c9): A RIOT powered balloon with sensors to monitor it's environment and an App that can display these information.
-* [Marian's Business Card](https://github.com/maribu/business-card): Hardware description, board support, games and text display software for business card sized board with USB power supply.
-* [Marian's demo boards](https://github.com/maribu/boards): Various PCBs, including an RGB Christmas tree board, along with RIOT board support for most boards.
+Icons indicate that the project offers
+hardware descriptions (![oshw]),
+a RIOT board description (![board]),
+RIOT modules (![module])
+or RIOT applications (![app]).
+
+* ![module] RIOT in space: [ThingSat.space](https://github.com/thingsat/) is using RIOT on CubSats to create an open source Low Power Global Area Network (LPGAN)
+* ![board] ![app] [MiniLoon](https://www.hackster.io/386121/miniloon-60a9c9): A RIOT powered balloon with sensors to monitor it's environment and an App that can display these information.
+* ![oshw] ![board] ![app] [Marian's Business Card](https://github.com/maribu/business-card): Hardware description, board support, games and text display software for business card sized board with USB power supply.
+* ![board] [Marian's demo boards](https://github.com/maribu/boards): Various PCBs, including an RGB Christmas tree board, along with RIOT board support for most boards.
 
 More lists
 ----------
 
 * [Hackster](https://www.hackster.io/riot-os) has an own list of projects using RIOT
+
+[oshw]: .icons/oshw.svg "PCB available as Open Hardware"
+[board]: .icons/board.png "RIOT OS board definition available"
+[app]: .icons/app.png "Application available"
+[module]: .icons/module.png "RIOT modules available"