This activity was engaging and really helped my students grasp how to use scale factor to enlarge or compress an image. I had the students pick their own Christmas/Holiday card to bring to class which made it personal and fun for them.
I used clear overhead transparencies and copied a 1cm grid onto them. I then laminated the transparency onto the Christmas card which helped speed the process along. Otherwise they have to draw on their own lines which can be challenging for some students.
I found that that the scale of 1cm to 2 cm grid to be simple enough, but I used a 1cm to 1 inch scale for students that might need a bigger scale. It really depends on the detail of the card.
The lesson took about 3 days. Two days to draw and one day to color.