Everyone has a world inside their head. Probably more than one. There are ways of getting from one world to another, but some of them are limited. You can take something from the physical world, for example, and use it to furnish the world in your head. The doors into your mind from the physical world are your senses... sight, hearing, taste, touch, smell.
You can even transport items or people from the world in your mind into someone else', whether through spoken word, fiction, sign language, poetry, television, etc. There are many doors between minds.
When you read a book, a door is opened wide between your mind and the author's. These doors are outside of time. You can have a direct connection to the mind of someone long dead.
The only door that either does not exist or simply can never be opened in this life is the door leading from your mind into the world. Once you have created something in the world in your mind, it is trapped. It can never enter the physical world. It can never make its own decisions. You have created a prisoner.
The only freedom available to your creations is access to the doors between minds. If you die without opening the doors, your creations will die with you. So don't be afraid to open the doors. Write books or songs or poetry or television, tell people your thoughts, and doors will be opened that may last forever.
As you have read this blog post, a door was opened between my mind and yours. This door transcends the bounds of time. I am writing these very words at 4:45 on Wednesday the 23rd. You are reading them at some point in the future. That is the power of language.