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Try something like this:
Make the tree and line as a black image with a white background.
Pre comp your tree and line to make a single comp.
Make a green solid layer and put it beneath your tree comp.
Make the tree comp invisible for now.
Apply a Venetian Blind (or Grid Wipe) effect to the green solid layer, in order to get the small horizontal scan lines. Don't keyframe it - the objective is just a tree made of thin lines.
Use a Track Matte on the green solid layer to reveal the shape of the tree layer above. Set it to Luma Inverted Matte.
Now you need to make the big blocks step in across the tree shape.
Make a new comp, and put a copy of your tree shape in here as a guide layer.
Set its opacity to 30% so you can still see it, but you can see everything else you're going to add.
Now we add some blocks:
To do this, I would use text squares in the correct shape around the tree, then animated using the Typewriter effect.
Do one set of these for the left to right blocks only, leaving a space for the right to left blocks.
Duplicate your "left to right" blocks layer, and scale its x-axis by -100
Make the two sets of blocks different colours so you can see what's going on.
Adjust the keyframes on the typewriter effect until they come in at the right rate.
Put your comp into your main comp (I called it "line draw ins") and make it invisible.
Go to the layer with your green scanline tree in it, and apply a Set Matte effect to it.
In the Set Matte effect, in the "Take Matte from Layer" setting choose your "line draw ins" layer. This is using your typewriter blocks as a matte (like the track matte we did earlier but can be anywhere in your comp).
Add in your text layer in the right colour
set some opacity key frames on it
then add an adjustment layer to make it look glowy and noisy, in whatever what your want to... (there are many tutorials on how to make things look like VHS videos). I put a glow and a channel blur on the adjustment layer.
Video example below: