its rough, but about right
|----------18-15-----------15--|-15-18-15-----------------------|
|-------15-------18-15--20-----|----------18-15-----------------|
|----16------------------------|----------------18-15-----------|
|-17---------------------------|----------------------/17-------|
|------------------------------|--------------------------------|
|------------------------------|--------------------------------|
|-------------12----------------|-------------------------------|
|-------------12----------------|------8------------------------|
|-------------12----------------|-7-10---/-3--------------------|
|-------15-17-------------------|------------5------------------|
|-15-17-------------------------|-------------------------------|
|-------------------------------|---------------3-3-6-3---------|