Hello JustCuteGirlzArt, thanks for explaining the rationale behind that arrangement of cast shadows in your organic intersections.

Having a reason for drawing the shadows in this manner is a good start, as it shows you were thinking about what you were doing, and means I'm able to give more specific advice on how to correct them.

To make it easier to understand which forms we're talking about, I've numbered them here.

So, if we consider the areas of shadow on forms 3, 4, and 5 that I'd previously highlighted in red. You've stated that they "are from the sausage form on the top." There are 3 forms that are above these shadows on the 2D space of the paper. 7 is too small and too far over to the left, so I'll discount that immediately. Forms 3 and 4 are casting shadows onto form 2, so by that logic 2 must be underneath forms 3 and 4 in 3D space. That leaves form 6, but we can see a shadow being cast from form 6 onto forms 3, 4 and 5 directly beneath form 6, as highlighted here. So I stand by my earlier statement that the areas highlighted in red here are illogical. I hope that better explains why these shadows cannot be present.

Your explanation for the gaps in the shadows I'd highlighted in blue seems to hinge on the shadows being lighter because the form is further from the ground plane. As you stated, we only have two values to work with, so, you need to fill the whole cast shadow with black. If you leave areas of your shadow white then it's not shadow anymore. We're ignoring things like reflected light and ambient light for this exercise.

You are correct in thinking that the distance between the form and the ground plane will affect the cast shadow. It just doesn't happen in this manner. I've put together some diagrams to help explain this visually for you. I'd also recommend grabbing a lamp or a torch and and examining the behaviour of cast shadows from household objects to gain a better understanding of this. The distance between the form casting the shadow and the form it is being cast upon (in this case, the ground) is going to affect the distance that the shadow gets projected, but the shape of the shadow will still be a projection of the shape of the form's silhouette.

So, if we treat the shadow you'd drawn being cast from form 5 onto form 1 as correct, then here is how the rest of the shadow being cast from form 5 might look. I've used a dashed line to indicate where the hidden parts of the shadow fall. I don't draw this when actually doing the exercise, but I thought it would be helpful to show the thought process here. By considering the shadow cast by the entire form we can see that even though form 5 is not resting on the ground we won't see a gap between the form and the shadow it casts on the ground. I hope that clears it up for you.