add light.typ code + assets and list in readme

a Typst file for visualizing linearly polarized electromagnetic wave
also deduplicate Typst and Latex code files before to avoid repetition in update-readme-table.py

assets/light/light.typ

@@ -0,0 +1,55 @@
+
+// adapted from https://github.com/cetz-package/cetz/blob/a082e02a/gallery/waves.typ
+#import "@preview/cetz:0.3.1": canvas, draw, vector, matrix
+
+#set page(width: auto, height: auto, margin: .5cm)
+
+#canvas({
+  import draw: *
+
+  // Set up the transformation matrix
+  set-transform(matrix.transform-rotate-dir((1, 1, -1.3), (0, 1, .4)))
+  scale(x: 1.5, z: -1)
+  let arrow-style = (mark: (end: "stealth", fill: black, scale: 0.5))
+  // Coordinate axes labels and arrows
+  draw.line((0, -2, 0), (0, 2.5, 0), ..arrow-style)
+  draw.line((-0.5, 0, 0), (8.5, 0, 0), ..arrow-style)
+  draw.line((0, 0, -1.5), (0, 0, 2), ..arrow-style)
+  content((0, 0, 2.3), [$arrow(E)$])
+  content((0, 3, 0), [$arrow(B)$])
+  content((8.7, 0, 0), [$arrow(v)$])
+
+  grid((0, -2), (8, 2), stroke: gray + .5pt)
+
+  // Draw a sine wave on the xy plane
+  let wave(amplitude: 1, fill: none, phases: 2, scale: 8, samples: 100) = {
+    line(
+      ..(
+        for x in range(0, samples + 1) {
+          let x = x / samples
+          let p = (2 * phases * calc.pi) * x
+          ((x * scale, calc.sin(p) * amplitude),)
+        }
+      ),
+      fill: fill,
+    )
+
+    let subdivs = 8
+    for phase in range(0, phases) {
+      let x = phase / phases
+      for div in range(1, subdivs + 1) {
+        let p = 2 * calc.pi * (div / subdivs)
+        let y = calc.sin(p) * amplitude
+        let x = x * scale + div / subdivs * scale / phases
+        line((x, 0), (x, y), stroke: rgb(0, 0, 0, 150) + .5pt)
+      }
+    }
+  }
+
+  // Draw waves
+  group({
+    rotate(x: 90deg)
+    wave(amplitude: 1.6, fill: rgb(0, 0, 255, 50))
+  })
+  wave(amplitude: 1, fill: rgb(255, 0, 0, 50))
+})

assets/light/light.yml

@@ -0,0 +1,10 @@
+title: Electromagnetic Wave
+tags:
+  - physics
+  - electromagnetism
+  - waves
+  - optics
+  - electromagnetic radiation
+  - Maxwell's equations
+description: |
+  Visualization of a linearly polarized electromagnetic wave propagating in the z-direction, showing the orthogonal electric (E) and magnetic (B) field components oscillating in phase. The electric field (blue) and magnetic field (red) are perpendicular to each other and to the direction of propagation, forming a transverse wave as described by Maxwell's equations. This is a fundamental representation of electromagnetic radiation, which includes visible light, radio waves, X-rays, and other forms of electromagnetic waves that travel at the speed of light in vacuum.

scripts/update-readme-table.py

@@ -13,11 +13,24 @@
 with open(f"{ROOT}/site/package.json", "r") as file:
     site_url = json.load(file)["homepage"]
 
-tex_paths = sorted(glob(f"{TEX_DIR}/**/*.tex") + glob(f"{TEX_DIR}/**/*.typ"))
+# Get all .tex and .typ paths
+tex_paths = glob(f"{TEX_DIR}/**/*.tex")
+typ_paths = glob(f"{TEX_DIR}/**/*.typ")
+
+# Create a dict mapping directory names to file paths
+# Prefer .typ files over .tex files when both exist
+path_dict = {}
+for path in sorted(tex_paths + typ_paths):
+    dir_name = os.path.basename(os.path.dirname(path))
+    if dir_name not in path_dict or path.endswith(".typ"):
+        path_dict[dir_name] = path
+
+# Convert back to sorted list
+unique_paths = sorted(path_dict.values())
 
 md_table = f"| {' ' * 22} | {' ' * 22} |\n| :---: | :---: |\n"
 
-for path1, path2 in zip_longest(tex_paths[::2], tex_paths[1::2]):
+for path1, path2 in zip_longest(unique_paths[::2], unique_paths[1::2]):
     dir1, dir2 = map(os.path.dirname, (path1, path2 or ""))
     fig1, fig2 = map(os.path.basename, (dir1, dir2))
 
@@ -31,7 +44,6 @@
     img_link2 = f"![`{fig2}.png`](assets/{fig2}/{fig2}.png)" if path2 else ""
     md_table += f"| {img_link1} | {img_link2} |\n"
 
-
 with open(f"{ROOT}/README.md", "r") as file:
     readme = file.read()
 
@@ -44,7 +56,7 @@
 )
 
 # update count in "Collection of **110** "
-readme = re.sub(r"(?<=Collection of \*\*)\d+(?=\*\* )", str(len(tex_paths)), readme)
+readme = re.sub(r"(?<=Collection of \*\*)\d+(?=\*\* )", str(len(unique_paths)), readme)
 
 with open(f"{ROOT}/README.md", "w") as file:
     file.write(readme)