add files & write README

rain.py

@@ -0,0 +1,58 @@
+#!/usr/bin/env python3
+
+'''
+terminal-rain - rain.py  
+Copyright (c) 2021 Julian Müller (W13R)
+License: MIT  
+'''
+
+import os, random, sys, time
+
+class Raindrop():
+    def __init__(self, posX):
+        self.posX = posX
+        self.posY = 0
+        self.symbol = "|"
+
+
+# array for the raindrops
+raindrops = []
+
+def generate_new_raindrops(n):
+    # generate n new raindrops per frame
+    for _ in range(n):
+        raindrops.append(Raindrop(random.randint(1, 1000) % (width + 1)))
+
+def remove_old_raindrops(x, n):
+    # when there are more than x raindrops, delete the last n
+    if len(raindrops) > x:
+        for _ in range(n):
+            raindrops.pop(0)
+
+def calculate_raindrop_locations():
+    # calculate the new position for every raindrop
+    for elem_ in raindrops:
+        if elem_.posY <= height - 1:
+            elem_.posY += 1
+        else:
+            elem_.symbol = "_"
+
+def write():
+    # clear the screen
+    sys.stdout.write("\u001b[2J")
+    # write the raindrops to the terminal
+    for elem_ in raindrops:
+        sys.stdout.write(f"\u001b[{elem_.posY};{elem_.posX}f")
+        sys.stdout.write(elem_.symbol)
+    sys.stdout.write(f"\u001b[H")
+    # flush the changes to the terminal
+    sys.stdout.flush()
+
+
+while True:
+    width, height = os.get_terminal_size()
+    generate_new_raindrops(3)
+    remove_old_raindrops(230, 3)
+    calculate_raindrop_locations()
+    write()
+    time.sleep(0.032)