diff --git a/waves.py b/waves.py
index c56aac9..4a5be27 100755
--- a/waves.py
+++ b/waves.py
@@ -6,13 +6,9 @@ from datetime import datetime
 import calendar
 import random
 import colorsys
+import argparse
 
 
-# dimensions of the output image
-# how much should the phases be offset?
-WAVE_OFFSET = math.pi / random.choice([1, 2, 4])  # -1.9
-# background black? White otherwise:
-DARK_BG = True
 # precision of the calculation
 PRECISION = 10000
 
@@ -35,7 +31,12 @@ def get_amplitude_from_date(date: datetime, waves) -> float:
 
 
 def create_wpotd(
-    width: int, height: int, date: datetime = datetime.now(), dark: bool = True
+    width: int,
+    height: int,
+    frequency: int,
+    wave_offset: float,
+    date: datetime = datetime.now(),
+    dark: bool = True,
 ) -> cairo.ImageSurface:
     surface = cairo.ImageSurface(cairo.FORMAT_ARGB32, width, height)
     ctx = cairo.Context(surface)
@@ -45,7 +46,6 @@ def create_wpotd(
 
     lastpoints = [(x / PRECISION, 0) for x in range(PRECISION + 1)]
 
-    frequency = random.randint(10, 40)
     waves = date.month
     amplitude = get_amplitude_from_date(date, waves)
 
@@ -68,7 +68,7 @@ def create_wpotd(
         x = 0
         while x < 1:
             # step along, create points along the wave
-            y = amplitude * math.sin(frequency * x + (wave_index * WAVE_OFFSET))
+            y = amplitude * math.sin(frequency * x + (wave_index * wave_offset))
             points.append((x, (y + (0.5 + wave_index) * wave_height)))
             x += step_size
         # print(f'Draw {len(points)} points for curve {num}')
@@ -87,12 +87,43 @@ def create_wpotd(
         ctx.fill()
         lastpoints = points
     return surface
-    # surface.write_to_png(output)  # Output to PNG
 
 
 def main():
-    output = create_wpotd(1920, 1080, dark=False)
-    output.write_to_png("out/waves.png")
+    parser = argparse.ArgumentParser()
+    parser.add_argument("width", type=int, help="Width of the image")
+    parser.add_argument("height", type=int, help="Height of the image")
+    parser
+    parser.add_argument("--dark", help="Draw on dark background", action="store_true")
+    parser.add_argument(
+        "-o",
+        "--offset",
+        type=float,
+        help="How much the waves should be offset to each other",
+    )
+    parser.add_argument("-f", "--frequency", type=int, help="Frequency of the waves")
+    parser.add_argument(
+        "--stdout", help="Write output image to stdout", action="store_true"
+    )
+    args = parser.parse_args()
+    print(args)
+    if not args.offset:
+        args.offset = math.pi / random.choice([1, 2, 4])
+    if not args.frequency:
+        args.frequency = random.randint(10, 40)
+    output = create_wpotd(
+        args.width,
+        args.height,
+        dark=args.dark,
+        wave_offset=args.offset,
+        frequency=args.frequency,
+    )
+    if args.stdout:
+        import sys
+
+        output.write_to_png(sys.stdout.buffer)
+    else:
+        output.write_to_png("out/waves.png")
 
 
 if __name__ == "__main__":