Below are the abstract, introduction, and conclusion of a computer science research paper. Please summarize the main contribution of the work in a single sentence. Your response should include the summary and no additional text.

Paper text:

We present sketch-rnn, a recurrent neural network able to construct stroke-based drawings of common objects.
The model is trained on a dataset of human-drawn images representing many different classes.
We outline a framework for conditional and unconditional sketch generation, and describe new robust training methods for generating coherent sketch drawings in a vector format.
Recently, there have been major advancements in generative modelling of images using neural networks as a generative tool.
Generative Adversarial Networks (GANs) BID6 , Variational Inference (VI) BID15 , and Autoregressive (AR) BID21 models have become popular tools in this fast growing area.
Most of the work thus far has been targeted towards modelling low resolution, pixel images.
Humans, however, do not understand the world as a grid of pixels, but rather develop abstract concepts to represent what we see.
From a young age, we develop the ability to communicate what we see by drawing on paper with a pencil or crayon.
In this way we learn to express a sequential, vector representation of an image as a short sequence of strokes.
In this paper we investigate an alternative to traditional pixel image modelling approaches, and propose a generative model for vector images.
Interpolation of two different Kanji characters (亀→書) as sequence of strokes (right).Our
goal is to train machines to draw and generalize abstract concepts in a manner similar to humans. In
this work, as a first step towards this goal, we train our model on a dataset of hand-drawn sketches, each represented as a sequence of motor actions controlling a pen: which direction to move, when to lift the pen up, and when to stop drawing. In
doing so, we created a model that potentially has many applications, from assisting the creative process of an artist, to helping teach students how to draw.This paper makes the following contributions: We outline a framework for both unconditional and conditional generation of vector images composed of a sequence of lines. Our
recurrent neural network-based generative model is capable of producing sketches of common objects in a vector format. We
develop a training procedure unique to vector images to make the training more robust. In
the conditional generation model, we explore the latent space developed by the model to represent a vector image. We
also discuss creative applications of our methodology. We
make available a dataset of 50 million hand drawn vector images to encourage further development of generative modelling for vector images, and also release an implementation of our model as an open source project.
In this work, we develop a methodology to model sketch drawings using recurrent neural networks.
sketch-rnn is able to generate possible ways to finish an existing, but unfinished sketch drawing.
Our model can also encode existing sketches into a latent vector, and generate similar looking sketches conditioned on the latent space.
We demonstrate what it means to interpolate between two different sketches by interpolating between its latent space, and also show that we can manipulate attributes of a sketch by augmenting the latent space.
We demonstrate the importance of enforcing a prior distribution on the latent vector for coherent vector image generation during interpolation.
By making available a large dataset of sketch drawings, we hope to encourage further research and development in the area of generative vector image modelling.
We investigate alternative to traditional pixel image modelling approaches, and propose a generative model for vector images.