cargo install ledcat

git clone https://github.com/polyfloyd/ledcat.git
cd ledcat
cargo build --release
cp target/release/ledcat /usr/local/bin/ledcat

# Make a strip of 30 apa102 leds all red.
perl -e 'print "\xff\x00\x00" x 30' | ledcat --geometry 30 apa102 > /dev/spidev0.0

# Receive frames over UDP.
nc -ul 1337 | ledcat --geometry 30 apa102 > /dev/spidev0.0

# Load an image named "image.png", resize it to fit the size of the display and
# send it to a ledstrip zigzagged over the Y-axis.
convert image.png -resize 75x8! -depth 8 RGB:- | \
    ledcat --geometry 75x8 --transpose zigzag_y apa102 > /dev/spidev0.0

# A clock on a zigzagged two dimensional display of 75x8 pixels
while true; do
    convert -background black -fill cyan -font Courier -pointsize 8 \
        -size 75x8 -gravity center -depth 8 caption:"$(date +%T)" RGB:-
    sleep 1;
done | ledcat --geometry 75x16 --transpose zigzag_y apa102 > /dev/spidev0.0;

# Show random noise as ambient lighting or priority messages if there are any.
mkfifo /tmp/ambient
mkfifo /tmp/messages
cat /dev/urandom > /tmp/ambient &
./my_messages > /tmp/messages &
ledcat --input /tmp/ambient /tmp/messages --exit never --geometry 30 apa102 > /dev/spidev0.0