The Main Riff is basically this:
|--------------------12\------|
|------------10------14\------|
|0*---10/12-----12------------|
|-----------------------------|
|--------------------12\--9\--|
|------------10------14\--10\-|
|0*---10/12-----12------------|
|-----------------------------|
(* The open A changes to 8 and then 5 for the F and D (The first F occurs at 0:35, and
first D at 1:28).
(F)
[ Tab from: https://www.guitartabs.cc/tabs/l/liquid_tension_experiment/osmosis_btab.html ]
|--------------------12\------|
|------------10------14\------|
|8*---10/12-----12------------|
|-----------------------------|
|--------------------12\--9\--|
|----------10--------14\--10\-|
|8*---10/12-----12------------|
|-----------------------------|
(D)
|--------------------12\------|
|------------10------14\------|
|5*---10/12-----12------------|
|-----------------------------|
|--------------------12\--9\--|
|------------10------14\--10\-|
|5*---10/12-----12------------|
|-----------------------------|
