#!/bin/bash
 
LINES=$(tput lines)
COLUMNS=$(tput cols)
 
declare -A snowflakes
declare -A lastflakes
 
clear
 
function move_flake() {
i="$1"
 
if [ "${snowflakes[$i]}" = "" ] || [ "${snowflakes[$i]}" = "$LINES" ]; then
snowflakes[$i]=0
else
if [ "${lastflakes[$i]}" != "" ]; then
printf "\033[%s;%sH \033[1;1H " ${lastflakes[$i]} $i
fi
fi
 
printf "\033[%s;%sH*\033[1;1H" ${snowflakes[$i]} $i
 
lastflakes[$i]=${snowflakes[$i]}
snowflakes[$i]=$((${snowflakes[$i]}+1))
}
 
while :
do
i=$(($RANDOM % $COLUMNS))
 
move_flake $i
 
for x in "${!lastflakes[@]}"
do
move_flake "$x"
done
 
sleep 0.1
done