As the Professor spoke about meanings, Spike got completely and utterly lost...and instead watched the changing colour of his stick. 'Flashing' was overstating the effect somewhat, but it was going from black to green and that was an achievement. However slowly the green appeared...

He tuned back into the Professor at the word homework. He pulled a face. Didn't the teachers realise there were so many more exciting things to be doing at Hogwarts than homework? He still had hide and seek to play, and a giant squid to tickle!

Meh.

AND he apparently had to do another spell on his stick. Picking up his wand, Spike spied the end which had the number he'd drawn on it. The eight was only visible whilst the colour was green, which meant waiting a fair while for the black to disappear. Dum-de-dummmm... "Fortunus lignum," he said, tracing the curved lines, carefully.

Did it glow? Or was that just the shade of green getting lighter as the black faded away? Hmmmm...