This exercise is about getting used to drawing leaves and other similar forms. The specific characteristics we're talking about when we're discussing leaves is that they're flat, but they flow through 3D space. This makes them extremely similar to the arrows exercise in lesson 2.

The great thing about leaves is that they very much stand as a representation of all the forces that are applied to them. Usually this is a matter of wind or air currents, but they are a physical object that will warp and shift to become a visualization of these forces.

As such, I want you to think of these as being more than just static objects with a clear start and end point. Just as you would when doing the arrows exercise, think of the forces that push through these leaves, and draw them with an awareness of how they flow through space.

1. The most important part is the center line, the spine of the leaf. I can't stress enough how important it is to think about how this line moves through three dimensions, not across a flat page, and to really drive home how it flows. No part of the leaf is more important than this, as it represents the forces that drive the form as it flows through space. I frequently draw this with a little arrow head to remind myself of how confidently it pushes onwards.

2. Enclose the leaf with simple curves. I don't care how complex this leaf is, capture the core of it, its essence, in just two curves. No waves, no jagged edges, no complexity whatsoever. Focus on the flow of the shape, and construct it around that center line. Don't treat that line like some kind of a suggestion - it is a rule. Build your leaf around it.

3. Using reference images, add some more complex edge detail to your simple leaves. Do not zigzag back and forth - add individual bumps or cuts one at a time, coming off the existing, simple edge, and returning to it.

4. And finally, detail. Don't stress too much over this, it's the absolute least important part of the drawing. A leaf with poor underlying construction cannot be saved no matter how much detail you add - it'll still feel stiff and lifeless. A strong construction with no detail whatsoever however will still look fine.

One common issue I see from students is the tendency to draw leaves (be it as part of this exercise, or when using the technique as part of their drawings) without much consideration for the flow line. This results in leaves that feel stiff and does not flow through 3D space in a convincing manner.

It's pretty easy at first to end up being a little nervous about making your leaves twist and turn in three dimensions, but often times that is what is physically demanded, due to the fact that they don't stretch much. Don't be afraid to let your leaf fold back over itself - let the flow line determine your choices, not your anxiety in what will and won't look good.

Construction is all about moving from simple to complex, breaking problems down into their most basic components and tackling only one challenge at a time. I often see students who see a leaf with many different 'arms', but who seek to apply the leaf construction method to the whole thing the same way every time, rather than thinking about why we employ these steps.

It's not that this is the only recipe that is going to work for every single leaf out there - it's that working around a dedicated line to determine how the form flows through space allows us to pin down that challenge before figuring out how the bounds of the leaf can be determined. If we jump straight into establishing the leaf 'shape', we have to handle both the flow and the surface area of the leaf simultaneously.

When tackling a leaf with multiple arms, you can absolutely start your basic leaf construction, establishing the flow and bounds of your overall shape, and then break internal components down by applying these steps to each individual arm. This will allow you to nail how each one's going to flow on its own, within the context of the larger leaf, before answering further questions.

When adding detail like little waves or jagged edges to a leaf, don't do so by applying a single continuous zig-zagging stroke. If you remember back to markmaking in lesson 1, the third rule is to ensure that each stroke consists only of one trajectory.

This is easy to separate when you've got sharp corners, but when you're dealing with more rounded waves as shown here, it may be a little less clear. In general, rise up off the edge from your previous phase of construction and come back down to it, then lift your pen and start a new stroke for the next bump.

Additionally, wherever possible, work additively - don't cut back into what you've already drawn, as this often makes us think more about the flat shapes on the page, rather than the solid, 3D forms they represent. In this case you'll notice very clearly that along the top edge of the correct example, I've come up off the edge and back down to it.

The other side however does seem to cut back into the leaf, but if you think about it in three dimensions, it doesn't. Instead, those edges are being lifted up slightly from their previous position, rather than being cut into.

There will be times when you cannot avoid having to work subtractively, but you should always do your best to see if there is a way to make additive construction work.

Another thing people tend to struggle with is stems, branches, and that sort of thing. Much of the challenge comes from the fact that these things are skinny and long, leaving very little room for drawing well shaped contour lines that wrap convincingly around the cylindrical shaft. This exercise focuses on taking the opposite approach - starting off with ellipses, and then constructing a tube around them.

This exercise exposes you to several important things. First off, the importance of the minor axis in relation to how ellipses should be aligned. Secondly, considering a tube to be a connected chain of ellipses, where those ellipses' degree reflect their orientation relative to the viewer.

Now, one thing is certain - this is not easy. The most difficult part is drawing the actual edges of the tube, connecting up the ellipses. You'll see that even in my example, some are worse than others. We'll discuss certain approaches to overcoming this challenge, but a lot of it comes down to practice. Also rotate your page. A lot.

1. Again, just like the leaves, start off with a simple line. It drives how your tube flows through space. Place ellipses along the line, being sure to align them to the line as their minor axis. I cover this in Lesson 1 as well as in the 250 Cylinder Challenge, but basically the minor axis cuts the ellipse into two equal, symmetrical halves down its narrower dimension. Also, consider the degree when drawing the ellipses - how fat or skinny the ellipse is is a product of how the circle it represents is turned in space. If it's narrower, it's turned away. If it's wider, it's turned towards the viewer. One way to think about this is holding up a CD and turning it slowly. As the tube flows through space, it will turn, so some of its cross-sections will be facing the viewer, while others will face away.

2. Draw the edges of the tube by connecting the ellipses. Drawing curved lines can be very difficult, especially when they have to match a very specific criteria. Do not draw a line from one ellipse to the other and stop. Instead, overshoot the second ellipse, trying to follow the path towards the third one and stopping fully halfway there.

3. Then go back to that second ellipse and repeat the process. Use that last half chunk of the previous segment as a runway, overlapping it directly (even if it went off course) and then continue on.

After enough practice - and this is a long ways away - you will find yourself being able to manage two, or three segments at a time. If you feel a segment is just too long and too curvy to manage, throw an extra ellipse in there to bridge the gap.

Start off simple, for at least half of the page. Then try playing around with it. Try adding small clusters of two or three ellipses close together, and once your basic branch has been constructed, place a ball between them to create a bulge or knot, as one sometimes sees in plant stems and branches. You can also try to add an additional branch sprouting from this bulge. You'll find more information on this sort of thing at the bottom of this page. When doing so, make sure your intersection points are clearly defined with ellipses, as it's these intersectional cross-sections that really reinforce the illusion of form.

Absolutely NEVER leave a tube open-ended, even if your image cuts off there. Always cap it off with an ellipse.

While we do focus heavily on building our ability to draw singular, continuous lines (as per the markmaking rules from lesson 1), there are situations where we are faced with long, complex curves that we simply cannot achieve in a single stroke. In these situations, we draw these longer lines in segments (what I will call a compound stroke), making sure to overlap these segments and have them flow smoothly and seamlessly from one to the next. It is something like a more planned, far better executed approach to chicken-scratch, but without the mess that comes with it.

Once you're more comfortable with the issues listed above, you can play with creating forking branches and knots, as shown here. Make sure that your initial branch forms are drawn with a consistent width, and that you're only focusing on one such branch at a time - when focusing on constructing one element, don't think ahead to the next, so you don't end up splitting your attention.