diff --git a/waves.py b/waves.py
index 1d5a594..c56aac9 100755
--- a/waves.py
+++ b/waves.py
@@ -6,71 +6,75 @@ from datetime import datetime
 import calendar
 import random
 import colorsys
-from utils import random_color
 
 
 # dimensions of the output image
 # how much should the phases be offset?
-WAVE_OFFSET = math.pi / random.choice([1, 2, 4]) #-1.9 
+WAVE_OFFSET = math.pi / random.choice([1, 2, 4])  # -1.9
 # background black? White otherwise:
 DARK_BG = True
 # precision of the calculation
 PRECISION = 10000
 
+
 def get_color_from_date(date: datetime) -> tuple[float, float, float]:
-    '''Return a color based on the progress through the year.'''
+    """Return a color based on the progress through the year."""
     # a day between 1 and 365 (inclusive)
     today = date.timetuple().tm_yday
     days_in_year = 365 + calendar.isleap(date.year)
     # between 0 and 1, how far through the year are we?
-    progress = today/days_in_year
+    progress = today / days_in_year
     return colorsys.hsv_to_rgb(progress, 1, 0.9)
 
+
 def get_amplitude_from_date(date: datetime, waves) -> float:
-    '''Return the amplitude of waves, based on progress through the month.'''
+    """Return the amplitude of waves, based on progress through the month."""
     days_in_month = calendar.monthrange(date.year, date.month)[1]
-    max_amp = 1/waves/2
-    return date.day/days_in_month * max_amp
+    max_amp = 1 / waves / 2
+    return date.day / days_in_month * max_amp
 
-def create_wpotd(width: int, height: int, date: datetime = datetime.now(), dark: bool = True) -> cairo.ImageSurface:
+
+def create_wpotd(
+    width: int, height: int, date: datetime = datetime.now(), dark: bool = True
+) -> cairo.ImageSurface:
     surface = cairo.ImageSurface(cairo.FORMAT_ARGB32, width, height)
     ctx = cairo.Context(surface)
 
     ctx.scale(width, height)  # Normalizing the canvas
-    #ctx.set_antialias(cairo.Antialias.BEST)
+    # ctx.set_antialias(cairo.Antialias.BEST)
 
-    lastpoints = [(x/PRECISION, 0) for x in range(PRECISION+1)]
+    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)
 
     r, g, b = get_color_from_date(date)
-    alpha_step = 1/waves
+    alpha_step = 1 / waves
 
-    ctx.rectangle(0, 0, 1, 1)
+    # background color
     if dark:
-        # make bg black
         ctx.set_source_rgb(0, 0, 0)
     else:
         ctx.set_source_rgb(255, 255, 255)
+    ctx.rectangle(0, 0, 1, 1)
     ctx.fill()
 
-    wave_height = 1/waves
-    step_size = 1/PRECISION
+    wave_height = 1 / waves
+    step_size = 1 / PRECISION
 
-    for wave_index in range(waves+1):
+    for wave_index in range(waves + 1):
         points = []
         x = 0
         while x < 1:
             # step along, create points along the wave
             y = amplitude * math.sin(frequency * x + (wave_index * WAVE_OFFSET))
-            points.append((x, (y + (0.5 + wave_index)*wave_height)))
+            points.append((x, (y + (0.5 + wave_index) * wave_height)))
             x += step_size
-        #print(f'Draw {len(points)} points for curve {num}')
+        # print(f'Draw {len(points)} points for curve {num}')
         else:
             # make more transparent toward bottom
-            ctx.set_source_rgba(r, g, b, 1 - (alpha_step * wave_index)) 
+            ctx.set_source_rgba(r, g, b, 1 - (alpha_step * wave_index))
         # draw waves
         ctx.move_to(*points[0])
         for p in points[1:]:
@@ -83,11 +87,13 @@ def create_wpotd(width: int, height: int, date: datetime = datetime.now(), dark:
         ctx.fill()
         lastpoints = points
     return surface
-    #surface.write_to_png(output)  # Output to PNG
+    # surface.write_to_png(output)  # Output to PNG
+
 
 def main():
     output = create_wpotd(1920, 1080, dark=False)
-    output.write_to_png('out/waves.png')
+    output.write_to_png("out/waves.png")
+
 
-if __name__ == '__main__':
+if __name__ == "__main__":
     main()