# Read four random bytes.

RAWVAL1=$(dd if=/dev/random bs=1 count=1 2> /dev/null)

RAWVAL2=$(dd if=/dev/random bs=1 count=1 2> /dev/null)

RAWVAL3=$(dd if=/dev/random bs=1 count=1 2> /dev/null)

RAWVAL4=$(dd if=/dev/random bs=1 count=1 2> /dev/null)

# Calculate the ordinality of the bytes.

XVAL0=$(ord "$RAWVAL1") # more on this function later

XVAL1=$(ord "$RAWVAL2") # more on this function later

YVAL0=$(ord "$RAWVAL3") # more on this function later

YVAL1=$(ord "$RAWVAL4") # more on this function later

# We basically want to get an unsigned 16-bit number out of

# two raw bytes.  Earlier, we got the ord() of each byte.

# Now, we figure out what that unsigned value would be by

# multiplying the high order byte by 256 and adding the

# low order byte.  We don't really care which byte is which,

# since they're just random numbers.

XVAL=$(( ($XVAL0 * 256) + $XVAL1 ))   # use expr for older shells.

YVAL=$(( ($YVAL0 * 256) + $YVAL1 ))   # use expr for older shells.